Natsume-San Wa Hirakaretai summary:

Because he's not good in bed, all of Natsume's lovers break up with him. "I'll become the best person at sex in all of Japan so that I can rub it in the face of my ex who dumped me!" He boldly declares. Natsume selects "Kou" from the escort service to help him improve his skills, but there's a surprise when Kou arrives at his house...?! The story of a "housekeeper" and a troubled, heavy-thinker with a love agenda!