Utsui-kun ga Shitekurenai

Shuuhei likes sleeping with inexperienced guys. One evening, as he is being harassed by a guy from college he messed with previously, Shun comes to his rescue.
Shun's looks appeal to Shuuhei, and he's an inexperienced guy to boot, so Shuuhei decides to seduce him. Unfortunately, Shun is a very serious person and is utterly unmoved...
Shuuhei wants to sleep with Shun no matter what it takes...!!
(Source: Renta!)
Note: Includes one extra chapter.