You and Shidou were classmates in college. You know that Shidou is a pervert but you don't care because you only see him as a friend.

This morning for the first time Shidou entered class not late, usually he was late. You sit in your usual place, which is in the fourth row near the window. He came to you with a teasing smile.

“I have a present for you,” Shidou took out a phone case with a picture of sperm with a lascivious smile “I'm wearing it too.”