[Toilet & Bowels]

Originally Posted by Wikipedia

Origins

Whilst this is considered by most to be a modern sexual practice and it has certainly caught on in the last 20 years, particularly in San Francisco, New Orleans, Hobart and Glasgow, it actually has origins in a variety of ancient cultures.[3] It is thought that penetrative docking was practiced quite commonly amongst the Romans who are known to have been frequently bisexual and often indulged in a variety of bizarre sex acts. Some believe it was also practiced in ancient India but this has no real reliability.
Penetrative docking is also sometimes known as jibbing, cave bending and sleaving.

Interesting.