Dogeza Shite Shojo Sotsugyou Shimashita.

Arumi Suzuki (25), loves her job as a mechanic in her dad's automobile repair shop, even while feeling envious of her friend who just announced her marriage. The truth is, even she wants to fall in love, but how in the world could she get herself a man? And then, to her shop came along an unexpected chance!? She approaches a customer of the shop — her old classmate who she hasn't seen in a long time — and tells him: "Please teach me how to have sex."

(Source: DMM, translated)

Note: Published in COMIC Megastore Alpha 2016-03.