I love it from behind! (1981)

A young girl named Mimei is working hard to get as many “penis prints” as possible. She’s been collecting these works of art since high school, and her goal is to get 100 prints before her arranged marriage within the next month. Seeking help from her lesbian friends Masumi and Rei, she begins chasing various men around Japan. Mimei finally gets her last man and is met with a challenge! He’ll allow her to make a print of his penis only if she can make him achieve ultimate ecstasy. She accepts, but finds out getting what she needs is a lot harder than she imagined!