Cream Lemon is an anime series. It is a collection of short stories. There are many different types of stories in the anime, for example, soap opera (the Ami series), fantasy (Rall series), horror (Cream Lemon Dark) and parody (Pop Chaser). It deals with a lot of heavy perversions including S&M, men being raped by groups of women, bondage, torture, yuri and incest.
Project A-ko was originally intended to be a part of this series.