Mud Lake 

To piss out your ass into a toilet bowl creating the effect of a mud filled lake.

Dude, you got to come upstairs and check out the mud lake in my toilet.

Mud Lake by Ricflairsayswoo September 22, 2009

Mud lake 

The aftermath of shitting during or immediately following a rimjob.

Michelle left a mud lake on Toms bed while he was rimming her.

The mud lake was a nice relief after the rimjob Mike gave me.

Mud lake by Moist oyster June 18, 2019