While much lighter on fan-service than most romance/harem anime, you will get maybe two scenes of girls in a bathtub, but you don't see any actual nudity.
There is a brief shot of a naked man from behind in an art class.
More than once, we see girls in a bra/bikini.
The main character shares a kiss with one girl.
A young man asks a minor to buy him a porn magazine as a prank.
A boy is said to have once had a crush on his older sister.
A young man walks in on a teenage/preteen girl bathing. Both are completely nude, but we don't see any sensitive areas. The young man jokingly offers to join her. The scene isn't so much sexual as it is awkward.