the story is a bout a young boy who is asked to go some where with his senior classmates and he wakes up tied to a post in a closet. They then suggest taking turns having sex with him, but they end up putting their stuff in at the same time. after that they ask who he likes the best and he says both so they start dating.

Hi I'd like that puppy in the window with the waggly tail. Oh that puppy, you don't want that puppy it's got caaannncer.

Moved to Yaoi/Yuri~

It's Hoshino Lily's "Youkubari wa Damerano," which is the last one-shot (chapter 6) from Nurse ga Oshigoto.