Any manga with the seme as a bully.
Do you know any?

Do you mean semes who are 'schoolyard' bullies, such as in Interval?
Or sadistic semes who just like to torture their uke, such as in Viewfinder?

Ijimetaihodo Aishiteru 1 story

You must read Ijiwaru na Aitsu right now. You might also like Sono Yubi Dake ga Shitteiru (both of them are shounen-ai, not yaoi though so I hope that is alright).

You could also try Kill Me Kiss Me, but it is more gender-bending (a girl dressing as a boy). A lot of questioning sexuality... but not actually shounen-ai. Still fun though.

[color=blue]THE SOUND OF THE OCEAN IS DEAD
[/color][color=gray]IT'S JUST THE ECHO OF THE BLOOD IN YOUR HEAD[/color]

Aitsu no Daihonmei

[img]http://i32.photobucket.com/albums/d25/khmershinobi/b750d351697e8dd4b2600bce2a15e1e9-2-2.jpg[/img]

__ I'll have what she's having... please~♥