Manga by author Nobana Saori

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...

"Please let me take responsibility!!"Rui, a pharmacist, is a sexual pleasure seeker. One day, he brings a completely drunk virgin, Takanashi, back to his place. Although they were extremely compatible sexually, Rui leaves the hotel, thinking it was his usual one-night stand.However, to his surprise, Takanashi says, "It looks like I fell in love with you, Rui-san.", and begins his aggressive pursuit. Despite being a bit put off by Takanashi's almost-stalker-like affection, which includes getting a part-time job at Rui's workplace while constantly checking up on him, Rui's heart begins to waver as he sees Takanashi's sincere devotion to him...+