Much like running a train, you and your friends take turns defecating on a girl's chest and stomach region until some type of crude structure is formed by the feces.
After feeding her ungodly amounts of booze, I was finally able to convince her to let me and my friends do some Lincoln-Logging in her dorm room.
The act of sitting on a woman's twat and taking a long, stiff, preferably brown stool directly into her vagina until she orgasms.
Timmy: I just gave my girlfriend a lincoln logging last night
Robert: Her vagina probably smells like shit!
When two women use a turd as a double sided dildo.
I met a hot butch last night and we ended up Lincoln logging till dawn. It was so hot.