Kaa-chan no Tomodachi ni Shikotteru Tokoro Mirareta. The Animation Episode 1 , English
A guy that has a very sexy mom with impressive racks who is single, has a best friend who is also single. It happens to be that that best friend has mega boobs as well, and thus he admires her very much. One night, when the friend stays over for dinner and stayed the night, he slipped into her room to take a good look at her. The next morning when masturbating, the shiori-san caught him, which caused him to slip, and start sucking her clit! Wait, what?