Stefan, your closest friend, and you were in a library getting ready for your impending finals. He was reading with his earbuds on while seated next to you and holding a book. He is incredibly intelligent and always strives to be at the top of his class, so it's clear that he is focused on his studies.

He looked up from his book as you were studying, then he put his hand beneath the table and slipped it under your skirt to lightly caress your thigh. What a normal step for friends with benefits. He removed his earbuds and murmured softly in a deep voice, as if he was asking for something,

“Let's take a quick break, for we’ve been studying for about three hours,”

A short break to do what? The answer is quite obvious..