The classic male fantasy... a two-girl blowjob

"Secretaries under the desk is so twentieth century," Karen said. "But every guy in the universe dreams of having two girls sucking his cock at the same time, right?"

"But... uh, you're his sister," Amy said. "Isn't this crazy?"

"I think we've had this conversation," Karen said. "I'm using my brother for practice because he isn't as complete a jerk as most of the other guys in school. And also because I know he won't go bragging on doing me because that makes him a total pervert rather than a cool guy, right? And the good news is, he won't go bragging on getting a three-way with you either because, same reason."

Amy nodded slowly. "I guess that makes sense. It still seems weird to me."

"It is weird," Karen said. "So, shall we do it?"

Amy looked at Matt. "He just came all over me. Do you think he's up for more?"

"Hello ladies," Matt put in. "I am here, you know. You don't have to talk about me like I'm some alien who can't speak English."

"Looking at his dick," Karen said, "I think he's ready."