When you take a shit but there are skid marks left on or around the toilet seat. Can also be used in other places such as "Party in my boxers" or "Party in my car"
Example 1
Person 1: "Shit... What the fuck is that?"
Person 2: "Looks like he had a party on the toilet seat..."

Example 2
Ted: "Yo Joey, you better clean up that bathroom, I just had a party on the toilet seat and it went everywhere!"
by Bableforce January 23, 2012
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