All I know is that in this manga, the main character witnesses his younger brother and good friend kissing. The main character has feelings for the friend and saw that happen. That's all I remember. Please help! Thanks!

I'm not sure but is it Kitto kiss o sure toki by Kanda Neko. P.s I'm having a feeling that some other manga also had the same story line. I'll inform you if I remember.

Yup! Thts the one! Thank you very much! And I would very much like it if you would give me other yaoi suggestions similar! Thanks!