There is a whole subgenre of Japanese porn that features the "human toilet", a female sex slave tied up to be the permanent sex toy of anyone who wants to use her. This H-cup hottie is a creampie-all-you-like facility, a flesh-and-blood hole to be used by all the tenants in the apartment.
Whether it's photographing her or sketching her intimate parts, these men are free to do whatever they wish. She is always tied up and can only submit to their horny desires. It's not long before they bring in a second female "toilet".
Human Toilet Apartment features: