A perverse sexual act involving two people, (one of which must be a female or the act would be classified more accurately as: Glenn-docking) and the exchange of feces.
PartyA(male or female) takes a large to extra-large sized, firm, steamy(optional) shit into partyB(female)'s vagina.
Last night I thought it would be a good idea to try out some space-docking with my wife; I was wrong.... I had just gotten over the flu and my shit was still very soft with some chunks, at first everything was going well as the opening chunk was moving smoothly into her vagina... But then the softer flu-poo came rushing out in a terrible brown flow, (across her stomach and squirting through her butt-cheeks from two different directions). This was a very foolish attempt at a long lost art, and some say myth; I can tell you however it IS possible, with the right woman, and the proper, firm, log-shaped dookie. Needless to say this event ended our thirty-two years of blissful matrimony.