Horimiya

Horimiya is a manga series that received an anime adaptation which aired in 2021.

The story follows two classmates in high school who live a double life: Kyoko Hori is a trendy and popular student who dresses down when at home and takes care of both the house and her younger brother Sota, while Izumi Miyamura is a gloomy and distant glasses-wearing boy at school who actually has numerous piercings and tattoos. After meeting each other outside of school thanks to Sota, they learn each other's true identities and find out over time that they have a lot in common. They help each other keep their secrets intact at school, while also finding themselves getting closer.

OP
Izumi and Toru are seen with their shirts unbuttoned.

Episode 1
Izumi shows his tattoos to Kyoko and Toru.

Episode 2
Syu is changing his clothes when Kyouko peeps into the boys' locker room.

Episode 4
Izumi starts to undress when Kyoko asks to see his tattoos.

Episode 7
Izumi is briefly shirtless.