Relentlessly Seduced by Mr. Perfect

Chiaki is secretly dating her younger co-worker Akira, and although they're totally in love, she can't keep up with him in the bedroom. Akira's always ready for another round straight away, and Chiaki's been losing sleep because of it... To make things worse, Chiaki's rival at the office, Shogo, discovers their relationship! He teases her, asking if she's satisfied with "quick-draw" Akira, and says he'll keep quiet about it if Chiaki can bring Shogo pleasure!

(Source: Renta!)