Violent anal sex within the confines of a dirty bath tub. One that preferable has a drain clogged with pubic hair and old cum. As the water runs and fills the bath, it mixes with the excrements that spill from the newly stretched asshole, turning the water mud brown.
"She was a freak bro, we took a donkey mud bath on the first date!"
Alt..
"This she/he/it is dirtier than a donkey mud bath."
by Grandmas mothball September 3, 2017
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