Majime Girl to Seishun Lingerie

The high school girl Ran Umemiya visits an unfamiliar place by herself for the first time: a lingerie boutique. There, she meets a high school girl who is very particular about her underwear, and the store's saleslady who loves lingerie in all its forms. Ran will learn many new things about lingerie that she never knew before.

(Source: ComicWalker, translated)