Osananajimi ga Do M de Tsundere Nan Desu ga

From Hoshikuzuu Scans: Susume is a total and utter masochistic bottom. He blows his nights having fun with guys, no strings attached. His crazy lifestyle then catches the attention of his childhood friend, Momo. Susume knows this and also the fact that Momo likes him, but he pretends to be oblivious. But one day, Momo tells him that he's always loved him. And Susume's response to that was, "Let's try going out once", but...