Kanojo to Kare no Shuumatsu

Tachibana Kayo is beautiful, kind, capable, and admired by everyone at work. However, she's a plain hikkikomori on the weekends, and a virgin, to boot. Her neighbor and junior colleague at work, Shindou Kei, finds out, and tells her she should master having fun on the weekends in a fashionable way. From his lectures, their relationship starts turning into one where they often go out together?!

(Source: Decadence)