An act where male/female cum is inserted inside the anus as the owner of the anus defecates. This results in a muddy puddle. Can be used as a noun or a verb depending on the sentence.
"I wanna muddy puddle her so bad."
"He's gonna get a muddy puddle."
When you have a girl on her back for anal intercourse, you pull out and rub your member on her belly button to make it brown then unload in her belly button. Hence the mud puddle.
Troy: So how did your date go with Mindy?
Ernie: I didn't think anything was going to happen but before I knew it she was on her back and I was giving her a Texas Mud Puddle.
I met this super hot chick last night, and we had the most awesome sex, but then I had to go out & buy a new mattress because there was an enormous cuddle puddle!