This is the part of a story experiment that I decided I wanted to conduct. I've written a second story with the same beginning, but a decidedly different outcome. Things don't work so well for James in this timeline, but for a timeline where things go better, check out "A Whole Weekend of Passion"! Sequels to come, hopefully!
James stared at his sleeping older sister and her girlfriend in the semidarkness.
Ever since she had come home from college for Christmas two weeks ago, Samantha had been sleeping in the nude. James had seen her at a distance one night when she had forgotten to close her bedroom door and couldn't help but wander inside. He was not disappointed - Sam was apparently a fitful sleeper, and regularly kicked off her blankets to reveal her smooth, slim body and her large, milky tits to the cold midnight air. In that moment, James could not bring himself to care that he was standing over his sister, that the two of them had grown up together and cared about one another as family. All he felt was his hungry, throbbing cock.
He hadn't been able to bring himself to touch Sam, as much as he wanted to grope or fondle or even finger her. But that night and every night since, James pulled out his cock and jacked off over his sister's sleeping body until he brought himself to glorious, spine-curling orgasm. James had shot his load on Samantha's big tits, her firm, athletic stomach, her tight, round ass, her gracefully arching back, her strong, slender legs, and, once, her plump, pink pussy. James figured that she was such a restless sleeper that by morning, the cum had been rubbed into the sheets before it could dry on her skin, and his sister was none the wiser.
And, tonight, Samantha's girlfriend Paige had spent the night. Sam had come out as bi to their mom and dad a year and a half ago, and the family had been understanding and supportive. So, as a show of good faith, James and Samantha's parents had let Paige stay the weekend while they left town to visit an old business friend.
Things could not have been more perfect.
Paige wasn't built the same as Sam. She was shorter, stockier, with bright red hair that contrasted shockingly with Sam's dark brown. However, where Sam was slimmer, Paige was jaw-droppingly voluptuous. Her wide, rounded hips supported a huge, juicy ass, and her breasts were bigger than James's head and turned every shirt that dared attempt to contain them low-cut. James couldn't blame his sister - if he were a girl and Paige had decided to hit on him, he probably would have switched teams entirely.
So, after a languorous hour and a half of listening to his sister and her girlfriend having the loudest, most orgasmic sex he had ever heard, James allowed himself to peek through Sam's door. Page had draped herself over Sam's chest, their magnificent breasts pressed against one another, and the two had fallen asleep in each others' arms sweaty, sticky with each others' cum, and content with the world.
As James crossed the room to the two sleeping women, his erection was so overpowering that he could barely stand - and this was the first night in a whole weekend of sexiness. He stood over his sister and dropped his boxers.
James began to work his cock, pumping his engorged shaft with near desperation. His sister, her girlfriend, their naked skin in the half-light, their delicate curves and the softness of their flesh. It was almost too much for him. Much quicker than usual, James felt tension in his cock, and then finally the bursting release of orgasm.
James's cum shot out onto his sister's stomach, watching the thick gray trail ooze its way down her hipbones to soak the sheets beneath her. But, to his alarm, his cock continued to pump load after load onto his sister - several more wads onto her stomach, three thin streaks across her tits, and, to James's alarm, one ecstatic and venturesome strand across her sleeping face.
James froze, his hand still on his cock. He didn't know if he would be better off running out of the room, or staying as still as he possibly could. Seconds ticked by like hours, and despite the tension, he still couldn't help but admire his sister's cum-covered body, still accompanied by her sleeping, curvy girlfriend.
And then, after an age had passed, Samantha opened her eyes. She ran her tongue across her lips, licking up her brother's cum and smiling slightly. She looked at James and ran a slender, manicured hand from her neck to her supple breasts, gathering James's cum and smearing it across her body in a sticky, glistening sheen. She reached out to James, beckoning with her fingers, and James found himself leaning inward so that she could reach his dick.
Samantha had known all along. Or maybe she had suspected. But there wasn't an ounce of surprise on his sister's face as she played with the cum on her fingertips.
James felt his sister's slim fingers, still warm and slick with his sperm, wrap gently around his cock. The sensation was just as Jim imagined it would be, firm and gentle and close.
***
Then, Samantha's grip tightened, and she pulled hard on James's dick, causing him to stumble forward over the bed. Her expression had changed; she was livid. James gasped in surprise and pain.
"Caught you, you little shit," Sam growled. James heard Paige smacking her lips.
"Ugh," she groaned, "I think he got some in my mouth."
"Are you fucking serious?" Sam shouted. She tightened her grip on James's dick, which refused to go limp.
"Sam, please, that hurts," James whimpered.
"Yeah? You should have thought of that before you decided you wanted to molest me on a nightly basis. And then you had to bring Paige into it!"
"P-please..." The pain and the shame had caused James to tear up.
"Please