here's what I can still remember

-characterA seems to keep on losing his things
-characterB is a very popular guy at school
-characterA found out that it was characterB who keeps on stealing his things
-characterA went out with a classmate
-characterB soon seducted and stole that guy as well
-characterA realizes that characterB will keep on stealing his things because characterB seems to like him
-its a oneshot or a twoshot only

I don't know how to refer to them so I call them characterA and characterB, thank you for those who will help me know the title of this yaoi manga/doujinshi...

Jibun katte.?