Koitomo Triangle

For years now, Sakai's been nursing a crush on womanizer Nishimura. Every time Nishimura breaks up with a girl, he comes crying to Sakai, who hears him out... and in turn, has no choice but to "relieve" his stress and frustration by turning to his friend-with-benefits Kitada. One day, not long after Nishimura broke up with his girlfriend, Sakai sees him walking with a new one and can't contain his aggravation! As usual, he works out his feelings by getting with Kitada, but he forgot to lock the door, and Nishimura walks in, catching them in the act...!

(Source: Renta!)

Included one-shot: Midnight☆Dancer no Sakuryaku