Cum medicine
By: Date: 2021.10.23. Categories: Sex Stories Tags: , , , , ,

My wife Kellie and her sister Kristin sat in the doctors office waiting for him to return with results for Kristin’s recent blood work. She had been losing weight recently which wouldn’t be a big deal if she wasn’t already so petite. Kellie was worried enough that she had demanded that Kristin see the doctor.

Kellie was shocked when the nurse had weighed in Kristin at 87 pounds when they arrived. She seemed to be losing an addition pound every week or two. She was very short, under 5’ tall and was so skinny you could see her ribs. She had a tiny, cute butt, and very small tits that we’re little more than perfectly shaped 1/2 tennis ball-like protrusions from her small 28a chest. She was in nursing school currently but didn’t have a very busy work schedule, as she was in between semesters.

Kellie, on the other hand, was taller at 5’4”, and while also very skinny, with a rib cage and chest that were also very small at 32b. Both girls were blonde and had very cute faces. They were only 2 years apart in age, with Kellie being the older of the two at 26.

The doctor entered the room with a folder and a concerned look on his face. After sitting and clearing his voice he spoke, “Kristin, after doing your bloodwork and looking at Kellie’s previous bloodwork, it appears you both have a genetic disorder. Kellie, it seems that you don’t have any symptoms which we have a theory about. I’ll get straight to it. Kellie, I believe your husband’s ummm… dna… has been helping keep you healthy. The odds of his dna being a perfect match to counteract your condition are simply incalculable. We’d like to run some tests on him as soon as we are able. Another donor like him might be a 1 in a million occurrence.”

Kellie interrupted, “that is good to hear doctor, but how does this help Kristin?”

The doctor paused before saying, “Well… it doesn’t exactly… but there may be some non traditional ways to improve her condition. We can do a bunch of further tests, but I suspect… that your husbands… well… sperm… might be allowing your body to process nutrients that it would normally reject. I realize that this is difficult subject matter… if you’re ok with it I’d like to ask a few questions to verify our theories are correct.”

“Wow… ok… Of course, doctor, anything to help my sister!”, Kellie replied.

“Excellent. Again, some of these question might be awkward, but it is in your sister’s best interest if you answer truthfully. Now, how many times per week do you and your husband have sex?”, the doctor finished.

Kristin turned her head slightly toward Kellie, very curious as to the answer. She was a virgin and had always been attracted to Ethan, Kellie’s husband, and now she was going to get some exciting insight into their sex lives. Kellie responded, “well… ummm… do you mean… intercourse, doctor?”

The doctor replied, “yes, we’ll start with traditional intercourse.” He sat ready with a pen and paper to mark on a chart on his desk.

Kellie, blushing a bit, looked down at her knees and replied, “maybe 3-4 times per week.”

Kristin couldn’t hide a slight smile. She had suspected they fucked a lot.

“Excellent. Very healthy.”, the doctor replied. “Now then, do you ever engage in anal sex, and if so, how often? You see, as with suppositories, the absorption rate of medicines in the anal cavity is nearly 5-7 times greater than ingestion.”

Kristin’s eyebrows raised and she stopped smiling. She had no idea that she would get these kinds of insights today. She was sure her sister didn’t allow Ethan to fuck her ass.

Kellie closed her eyes, still looking down, reminding herself she HAD to be honest, “ummm… well… yes, doctor, I’d say we do that… well… once or twice per week.”

Kristin couldn’t help but allow her jaw to drop slightly as her eyes opened wider. she thought to herself.

The doctor made a note in the chart and replied calmly, “Thank you Kellie, I know the subject matter is difficult. I’m just trying to get a sense of how you’re absorbing his DNA, which is keeping your symptoms at bay. Just a few more questions. Now again, we’re trying to establish a pattern of ways you are absorbing your husband’s sperm, as I believe his DNA has been keeping you healthy. How often do you perform oral sex on your husband?”

Kristin started to feel aroused imagining what the answer might be.

Kellie sighed. This would be much easier to answer if her sister wasn’t in the room. “Well… I think… maybe once or twice…”

The doctor interrupted, “excellent thank you. Once or twice per week.” He began marking it down when Kellie interrupted him.

“No doctor, I’m sorry… I meant… well… I meant… once or twice… per day…” Kellie corrected, quite embarrassed and visibly blushing.

Now both Kristin AND the doctor looked shocked.

“…Excluding foreplay from intercourse.” Kellie finally finished. She felt she might pass out from embarrassment as the doctor marked his chart after a shocked pause.

Kristin also couldn’t hide her shock. Then she started to feel angry. She spoke up, “Kellie… this sounds like abuse. He shouldn’t be asking you to do that so much. Maybe you could use some counseling…?”

Kellie corrected her quietly and almost guiltily, “No Kristin, I’m the one that initiates it each time. In fact, there are some times where he seems too tired, but he knows I get upset if he doesn’t let me do it.”

Kristin stopped talking. Her sister was a sex addict?! This didn’t make any sense! She had only dated a few guys before Ethan, and didn’t even have a single boyfriend in high school! She wasn’t exactly the town slut before she got married!

The doctor interrupted her train of thought. “Kellie, In nature many species crave things that are necessary for their survival. It is highly probable that subconsciously you have been craving the cure for your condition. Now just a final few questions.”

He continued, “First, how often did you perform oral sex on previous partners?”

Kellie thought for a second out loud, “I only had 3 boyfriends before Ethan… and I didn’t really enjoy oral sex back then. Not often at all! It just that I enjoy it so much more with Ethan.”

Kristin was beginning to feel flushed and her pussy felt tingly, she could also feel her nipples getting hard. She glanced down self consciously at her shirt to see if it was noticeable. Thankfully she always wore extra padded bras to make her chest look bigger.

The doctor replied, “interesting. This is confirming my theory. Now… how often do you ingest your husband’s semen?”

Kellie responded quickly and almost defensively, “oh I never waste a drop of cum! Errr… sperm.” Jesus she sounded like a total slut! “I mean… I… I… ingest most of it every time, doctor.” Kristin wasn’t hiding her shock as she stared openly at her sister.

The doctor replied, “As I suspected. Now then, there are two possible solutions to Kristin’s problem. First, we can get a sample of your husband’s dna, and synthesize it. This process is very expensive, several hundred thousand dollars at least, and may take 6 months or longer to produce. This may require an extended hospital stay, during the wait, to provide a constant IV drip to provide you with the nutrients your body is not able to absorb naturally.”

Both sisters looked distressed. There was no way they could afford that much, and the thought of Kristin being hospitalized for 6 months was awful! Kristin spoke up, “and the second solution?”

The doctor paused briefly, “The second option is to give your husband… Ethan, was it?” Kellie nodded and the doctor continued. “To give Ethan a new medication that will greatly increase his semen production. He would have to be part of a test trial, but you can sign up for him.”

Kellie immediately knew what the doctor was implying. She inhaled and held her breath, looking down. Kristin however was slower to comprehend what was being suggested. She asked without thinking, “But… Doctor, how will that help ME?”

The doctor looked down as Kellie let out a sigh and grabbed Kristin’s hand. Suddenly realizing that the increase in semen production was for HER, she blurted out, “Oh my god! Kellie! No! I’ll have to find a way to save the money!”

The doctor interrupted and stood, walking to open the door as he said, “it seems the two of you have much to discuss. I’ll have the nurse call in a pre***********ion for your husband’s medication, if you’ll sign up for the trial at the front desk. I’ll have them ready the paperwork.”

Both young women walked out in a daze.


10 minutes later, halfway through their completely silent car ride home, Kellie finally spoke, “Ethan and I would do anything for you, Kristin… and this HAS to be done.”

“No. That isn’t an option. I could never ask this of you Kellie.”, Kristin replied. She noticed they weren’t driving towards her house. “Why aren’t we going to my house?”, she asked.

“I have to make a stop at the pharmacy for Ethan’s pills.” Kellie said as she put her turn signal on with a very slight smile. “Then we have to stop by my house briefly.” Before Kristin could freak out about going inside, Kellie added, “…you can wait in the car.”

She could sense Kristin’s relief. Kellie was forming a less direct plan. They finished at the pharmacy and pulled up to Kellie and Ethan’s house a few minutes later. “Be back in 5… ish…” she said cryptically and then ran inside leaving the car running with Kristin in the passenger seat.


Kellie ran into the house. She could hear Ethan working in the study. She pulled off her shirt and bra, ran into the kitchen, and grabbed a Gatorade from the fridge. She pinched her nipples while pulling them away from her small chest, and then took turns putting the ice cold Gatorade against each one. She almost yelped it was so cold. She opened the drink and drank nearly 1/4 of the liquid quickly.

Ethan walked in suddenly and raised his eyebrows after noticing her topless. Her nipples were rock hard. Fuck she was hot. What was she up to?? “Uhhh hi sweetie… how was your… ummm… day?”

She smiled flirtatiously and place a pill bottle on the counter, “Ohhh… pretty good… have to run back out in a few… promise me you’ll take these pills right when I leave? I’ll explain later but it is important that you take one. No questions please. I’m in a rush… but need some cum before I go.”, she said nonchalantly.

“Uhhhh… ok, what???”, Was all he could respond.

She rushed up to him and sank to her knees placing the Gatorade bottle between her legs, saying, “I need your cock down my throat, NOW!”, as she pulled down his shorts and began getting his semi hard cock harder with her mouth.

“Jesus!” Was all Ethan could say as she began. Usually she spent a few minutes trying to convince him to let her give him a blowjob. He didn’t mind her being assertive, though. This was hot.

He was rock hard in seconds, at his full 9 inches. She pulled her mouth off with a plopping sound, just long enough to practically shout, “grab the back of my head and skull fuck me! Force that big cock down my fucking throat, but warn me before you cum!!”

Ethan paused for a second before grabbing the back of her head. Jesus… she was a fucking slut. He was the luckiest man alive. Little did he know how lucky he was going to get in the next few days.

Impatient, Kellie put both hands behind her head, covering his, and jammed herself toward his cock. She made a loud gagging sound, backed off slightly and jammed herself forward again 3 times until his cock finally popped down her throat.

Ethan took over and began fucking her throat in amazement. She moved her fingers down to her still hard nipples and began pulling at them. She gave a whining moan every time he let her up for air. He took that as a sign to force her back down. It was getting easier to slide it back down with every thrust.

Fuck, he was already getting close to cumming and it had only been a few minutes! “I’m close!”, He shouted.

She could already tell that he was, based on his breathing. She moved one hand up and began massaging his balls aggressively. She used the other to pull his hands off of the back of her head and began massaging his cock with her throat and tongue. She grabbed the Gatorade bottle, pulled off of his cock and put the tip at the entrance to the bottle and began stroking him just in time for him to shoot load after load of semen into the bottle.

“Fuuuuuuuck!!!! What… are… you… doing??” He groaned between each spurt as he released his entire load into the bottle while she stroked him. He couldn’t remember the last time she didn’t greedily swallow all of his cum.

“Just grabbing some cum to go, sweetie!”, Kellie said as she squeezed his cock shaft from the base to the tip to collect the last few drops into the bottle, grabbed the cap and secured it. She suddenly stood up and grabbed a water bottle from the fridge. She shook up the bottle with the cum in it, grabbed her shirt without putting on her bra and kissed him on the cheek. “Thanks sweetie! Be back in a bit! Take your pills!!”, she said as she bounced happily toward the door.

Ethan stood there shocked as he watched her leave. God damn she was weird, and he loved her for it. He picked up the pill bottle, squinting at the instructions, counted out the number of pills he was supposed to take, and grabbed some water from the fridge to wash them down.

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