So, I Can't Play H! Things

Bikinis are typically two-piece swimsuits for women, available in many different styles and colors. It's like waterproof underwear.

Dakimakura is a portmanteau of "dakishime" (hugging) and "makura" (pillow). They are body pillows featuring (mainly) female anime characters and are meant to snuggle with.

Gym Uniforms are usually worn by students during Gym Class/P.E. and sometimes as cosplay. Typical gym uniforms consist of white t-shirts and bloomers for girls and shorts for boys.

A swimsuit worn by female students during swimming classes in Japan.

The character is wearing school uniform. Most probably he/she's a student.

A Swimsuit is a one-piece article of clothing that is designed for participating in different manners of water based events. Worn casually by the more modest.