The act where two people go anus to anus and then one of the participants has a bowel movement into the anus of the other participant. The second participant receives the fecal matter anally and then pushes it back into the anus of the original fecal matter owner.
Tim and Johnny have been getting quite messy with their new shifting logs experiment. Looks highly unsanitary but they seem happy.
Boss: "Are you coming into work today, Bud?"
Joey: "I'm not going to make it today, Boss. I got ahold of some bad street tacoslast night and I'm shitting like a goose this morning."