Kim and his sister.

"Today, I pick Kim and Sarah as my partners." Josh announced to the classroom.

Kim smiled and jumped up and down in excitement. Her large tits bounced up and down in approval. Sarah just rolled her eyes and crossed her arms over her naked chest. Taylor was the most disappointed since she was almost guaranteed not to cum as hard today, if at all.

The two girls walked over to Josh and the rest of the class got to pick their partners. Half the groups were mmf and the other half was ffm. Just like yesterday, the well endowed paired themselves with each other while the not-so-lucky were stuck staring at their partner's lackluster tools. Taylor, having gotten a grade boost from Josh's performance the day before, actually got to pick some average sized men for her threesome. Looks like she was going to cum today after all.

"Alright, boys and girls! Since threesomes are a little complicated than your standard one-on-one sex, grading will be a bit relaxed today." Mr. Wilder said.

"The minimum amount of effort you need today is to make one of your partners cum. Any additional orgasms will give you a higher grade. Three orgasms will net you the highest grade. Anymore is just showing off." Ms. Mulligan added.

"Take off your clothes everyone and I'll ring the bell to signify when you can start. You'll have until the end of class to make a partner cum. Remember, no cheating by rubbing yourself before the start."

Josh chuckled to himself. Making his sister and Kim cum would be extremely easy. Yesterday, Kim only took five minutes to cum before blue balling him in the computer lab. Sarah wouldn't take much longer assuming he'd let her cum.