His Sister's Girlfriend

“Oh, I don’t think that will be a problem,” the doctor cut her off. “Alex, why don’t you give your partner some assistance, what usually excites her?”

Without even thinking about it, Alex responded, “her breasts. Sarah’s breasts are very sensitive.”

“Ah, excellent,” the doctor said. “Then we won’t even have to shift positions. Sarah, you know your partner’s body, why don’t you just do a little manual stimulation there, and we will prepare for the insertion of James’ penis?”

Sarah wanted to say something, but before she could think of another excuse, some way to prevent James from finding out how turned on she was, the doctor had taken a step back and James had shifted his hips to place the head of his penis at her pussy. Alex had moved behind her head so that she could caress both of her breasts at the same time. Alex had been right, of course, she knew her partner’s body almost as well as her own, and her breasts were incredibly sensitive. Shivers ran up and down her spine as Alex caressed Sarah’s breasts, gently at first, running her fingernails around the outside and the incredibly sensitive skin underneath. Oh my god! she thought, this is incredible! I can’t let myself enjoy this too much, this is just for medical reasons, this is just so I can get pregnant.

Meanwhile, James had begun inserting his cock into Sarah’s pussy. He had noticed she was already dripping, even before his sister had begun stroking her breasts, and he smiled inwardly to himself. He was actually going to make this work, he thought, he was going to fuck his sister’s girlfriend. Dr. Madison had moved out from behind him and now stood at Sarah’s side. “I think we might want your legs spread just a little wider, Sarah,” she said as authoritatively as possible. “Let me make a quick adjustment.”

Before Sarah knew what was happening, another pair of hands was now stroking her legs, the doctor’s fingers running up the insides of her thighs. Oh fuck, she thought, if I wasn’t going to come before, I am definitely going to now! The doctor, ostensibly shifting her thighs apart, was also allowing her fingertips and nails to caress Sarah’s thighs as she did so, and the combination of that and her girlfriend’s stimulation of her breasts was about to drive her crazy. She could feel her pussy had gone from wet to dripping like a faucet, and James slowly and easily slid the length of his cock inside of her, burying himself to the hilt.

Sarah had never felt so full before in her life, every nerve inside her pussy was on fire, responding to the incredible length and girth of her partner’s brother cock inside her. Alex’s touch on her breasts had become more insistent, her partner’s nails now rubbing her skin and raising goose bumps all over her body, while the doctor’s caresses of her inner thighs were making her legs shake from excitement. She desperately did not want to come while being fucked, did not want to admit that a cock inside her like this could feel so good, but the stimulation of her entire body was not going to let that happen. The best she could hope for was that she wouldn’t give away to James how much she was turned on by his penis inside her.

James leaned forward slightly, pressing his stomach up against her, the base of his cock now rubbing up against her clitoris. She was so turned on he could feel it pressing against him, and he pretended to shift his weight and rubbed himself against her again, feeling her legs shake as her clit responded to his action.

“James,” Dr. Madison said, never letting her hands stop moving up and down Sarah’s thighs. “Let’s make certain that everything is working smoothly, why don’t you make sure you have decent freedom of movement. I have to imagine that Sarah is quite tight, especially given how large your penis is, correct?”

James nodded. “Yes, doctor, I can feel her holding me tight.”

For some reason, Sarah felt inordinately proud at James’ statement. Although she was not Gold Star, she had definitely had limited experience with men, and she was glad that her pussy was still nice and tight. Underneath that was also pride that she was making James feel good with her pussy, since he was making her feel so good with his cock inside her. It’s because he’s Alex’s brother, she said to herself. I am just happy because they are related, that’s all. He’ like half of Alex, right? So fucking him – oh my god he fills me up – is like fucking her, it’ just like fucking Alex, that’s all. Then the image came into her head of fucking them both at the same time, a wicked and hedonistic threesome with the brother and sister both pleasuring her and themselves. She tried to not indulge in that fantasy, tried to push it out of her head, even as Alex moved from the outside of her breasts to grab her nipples and start to squeeze them, sending even more flashes of pleasure through her body, up into her brain and down into and through her pussy. For a moment she thought she was going to black out, the pleasure was so intense, and then James shifted his hips, moving his cock out. He was so large, it was like a never-ending sensation as he moved his hips backward inch by inch.

“Please,” she whispered as she felt the head of his cock at her entrance, not even knowing what she was referring to. She wanted to think she was asking him to stop this absurd act, but she knew she wasn’t. She knew, even if she couldn’t admit it, that she was asking him to put it back in. Begging him to slide his incredible cock back inside her pussy, to fill it up and stretch her out, to claim it as his. She bit her lip to prevent herself from saying, or shouting, anything else, and instead simply let out a small whimper as James began the long slow slide back inside her.

When his hips pressed against hers, she couldn’t control herself however. Her breasts, her legs, her pussy, every inch of her was on fire, stimulated beyond her control. She bit down so hard on her lip to keep from crying out in pleasure that she tasted blood, but it could not prevent her intense orgasm, starting from the bottom of her toes, making her legs shake as it passed up her body, bucking her hips and making her breasts bounce in Sarah’s grip as she shuddered and quaked, coming over and over again in response to James fucking her, to Alex playing with her breasts, to the doctor massaging her thighs. Her pussy spasmed again and again around James’ cock, each contraction milking his cock, sliding her sensitive inner flesh back and forth across his incredible cock and setting off another explosion. The pleasure was so intense she blacked out for a moment, stars shooting through her vision.

Sarah reached out to grab Alex’s hair, and Alex was surprised as her girlfriend dragged her into a deep and passionate kiss. Seeing Sarah so turned on was overpowering her own willpower, and feeling Sarah’s soft tongue thrust into her mouth caused her own pussy to start dripping. She had already been excited watching her brother’s huge cock impaling her girlfriend, imagining that it was entering her own pussy, and playing with Sarah’s breasts at the same time had already turned her on so much she was a little worried she would attack her own brother and force him to fuck her. Now with her hands still kneading Sarah’s breasts, the incredibly sensual feeling of her girlfriend’s generous orbs overflowing her hands, and feeling Sarah’s body buck and jerk as she obviously orgasmed over and over in response to Alex’s own brother fucking her, Alex did the only thing she could to address her own overpowering urges, and removed one hand from Sarah’s breasts, ignoring the woman’s slight whimper, and it down into her own pants, desperately diving through denim and her cotton panties to find her own clitoris, grinding the palm of her hand against it while she slipped her middle finger into her own tight pussy, relishing how easily the digit slipped into her dripping wet pussy.

Again, knowing that that night she was going to fuck her girlfriend desperately while thinking about her brother’s cock, and so overcome in the moment that she didn’t even care, all she could focus on right now was the feeling of her finger in her pussy, her hand rubbing her clitoris, desperately bringing her own explosion of pleasure. She almost fell over as she came hard, the only thing keeping her upright were Sarah’s hands gripping her hair, still forcing her tongue into Alex’s mouth, and her grip on Sarah’s large breast. Squeezing tightly to keep from falling over set Sarah off again, the redhead’s hips bucking like she was trying to throw James off, but his cock remained firmly embedded within her.

Unnoticed by Alex and Sarah both, Dr. Madison gave up any pretense of medical professionalism and leaned over to suck and lick Sarah’s clitoris while James continued his slow and careful fucking of her pussy, now arching his back slightly to give the doctor room to orally pleasure his sister’s girlfriend while he fucked her. Sarah had just come down from her third or fourth intense orgasm, she had lost count, when she felt the warm wet mouth of the doctor descend on her pussy at the same time as Alex gripped her breast tightly and she could feel her girlfriend’s arm moving. Knowing that Alex was fucking herself allowed Sarah to finally give up any worry or self-control and surrender to the pleasure that had been building like a skyrocket and she came again, even harder than she had before, harder than she ever had in her life. She felt like she was drowning, and floating, and bursting into flames while being dowsed with water all at the same time.

Her back arched, her breasts desperately seeking more contact with Alex’s hands, her clitoris desperate for more contact from Dr. Madison, her pussy desperate for more of James’ cock. She felt every muscle in her body contract and relax and then contract again, her eyes rolled into the back of her skull and a long and loud gasp started in her throat, leading to a loud moan as she gave in to the sensations, knowing that she was being pleasured by three people, the center of their sexual attention and loving every moment of it. Then James came, she could feel his cock expand, getting thicker and filling her up even more, more than she could have imagined possible, and she felt every jet of sperm shoot out from his cock, coating the inside of her womb, shooting over and over again, every spurt making her come again, and she screamed in pleasure, not even trying to pretend like she was not enjoying this, enjoying being fucked by a big cock, that this was what she needed, and what she would need over and over again for the rest of her life.