I am quite sure it's this (but it's not really yaoi):
http://www.mangago.me/read-manga/uta_no_prince_sama/
I think it this story
http://www.mangago.me/read-manga/back_stage/
Yes, they are Masato and Ren from Uta no Prince-sama, there are a hundred of doujinshis about them.
http://www.renders-graphiques.fr/image/upload/normal/Uta-no-Prince-sama-Maji-Love-1000-Yaoi.png
http://static.zerochan.net/Uta.no%E2%98%86prince-sama%E2%99%AA.full.832839.jpg
Two more images, Yay!
http://iweb9.mangapicgallery.com/r/newpiclink/kiss_made_ato_3_senchi/1/a7b1dcdb1e1c0e5a3ce7a9f8289ebe4c.png