Futaba-kun Change

Futaba-kun Change is the story of a boy who changes into a girl whenever he becomes excited, and changes back when he is able to relax. Unfortunately, his family had not bothered to tell him this would happen (since they also change), and so he's caught offguard.

He's a high school student and is interested in girls, one in particular, and is a major player on the school wrestling team.

This is the girl he's interested in, Misaki. Both of them, though, are very shy, and they are not really at the girlfriend-boyfriend stage yet.

There's a lot of nudity and cultural-related jokes, like this panty shot of Misaki, and boys getting terrible nose-bleeds when they see a nude girl.

There were eight volumes of comics, and these were later collected into paperbacks. The series is sometimes compared to Ranma ½, and there are some similarities but more differences than similarities between the two.

Volume 1
Volume 2
Volume 3
Volume 4
Volume 5
Volume 6
Volume 7
Volume 8

These are the three paperbacks that I have.