Kojirase Doutei wa Akiramenai

Iku, a self proclaimed long-term virgin who dreams of losing his virginity, falls head over heels in love with Mashiro, the handsome manager of a café Iku happened to visit. Iku found Mashiro so attractive that he thought, "Yeah, I can do a guy instead!" and proceeded to pursue him. One evening, after a lovely date, Iku thought his chance had finally come to graduate from his virgin state. But for some reason it was Mashiro who was making him feel good...

(Source: Kadokawa, translated)