These stories about 4 typical high school girls' love life are Yokoyama Mayumi first work.

Story 1: A Real World

After 2 years Eri got back together with her ex-boyfriend.

Story 2: Lip Lock

Nina made him break his "right hand" so she substituted XX (sexual favours?) to take care of him.

Story 3: That Is My Weak Point

Risa's ex-boyfriend stole embarrassing photos of her, and now she wants to get them back.

Story 4: Hotel Red Peacock

With the current course of events, Chika needs to make her bad tasting Love Hotel prosper.

(Source: MangaRebels)