The action where you take a shit (dump) in a freshwater lake or river. It is popular with many people since it has been said to clean your asshole inside and out before AND after the large shit has evacuated the rectum. It also seems to feel good too.
Guy #1: Dude, I just took a FWD in Lake Michigan this morning.. now I don't have to shower today.
Guy #2: Man that's disgusting. I'm never swimming in that lake again
Guy #1: It's ok dude it'll just dissipate in a few hours.