From Renta!:

Komiya Tadashi wants to become the number one host. He does his best at every job, no matter how unpleasant, but he has one big weak point... He's really bad at sex. Because of that, his ranking is the lowest. One day, the owner of the club gives him directions for a secret plan. The plan is "The Special Instructions on Sex" from legendary host Hayato! Tadashi is reluctant at first, but he changes gradually. He rubs his ass up in an approach from himself, and Hayato's excellent technique has him screaming and coming endlessly! Tadashi is straight, but Hayato has his heart beating hard...!? It's a rocky road ahead for this love... What will happen!?