Katagoshi ni Nage Kiss

Chinatsu Kasuga is a lively 20-year-old department store worker She has a relationship with Naka-chan, who is younger than her, where they are more than friends but not quite lovers. However, when she is transferred to the men's clothing department, she meets Takamura-san, a reliable and wonderful man. Younger men are cute, but women still admire older men.

(Source: Kodansha, translated)