To his sister, of course

He knocked on his sister's door and then walked in.

Possibly a mistake. She was lying on her bed completely naked with her fingers in her pussy.

Fuck, that was hot. He froze in his steps, transfixed by her sexy muscular yet feminine body, her cute breasts, her blond hair splayed out on her pillow, and the wet noises coming from her pussy.

"Geez, loser. You don't walk in on a girl without knocking."

"I, uh, knocked."

"Yeah and didn't give me a chance to tell you to go away."

"Sorry."

"That's all you say? Sorry."

Actually he wasn't sorry at all. He would have paid multiple weeks of Mrs. Hartman's money for this sight. Yeah he'd seen dozens of girls masturbating on the web but this was different. Those masturbation sites didn't give you the smell of pussy and, he suspected, half the orgasms there were faked, just something to bring in the tips. He also wasn't sorry that Karen hadn't actually stopped masturbating when he'd walked in. Her fingers were still buried deep in her pussy, still moving, still making those wonderful noises.

"I can... come back later if you want."