A Mandatory Sex Party is a party where once you walk in the door, you are obligated to have sex. These parties often disguise themselves as costume parties, birthday parties, or baby showers. But THEN as soon as they entice people in the door, they are all "guess what this actually is? It's a mandatory sex party, bitch!"

Then the raping would commence.
"Last night, I went to my friends halloween party, only to discover that it was ACTUALLY one of his crazy Manditory Sex Parties. I had to get 7 stiches in my asshole and 9 in my mouth.
by CumBucket69HellWhore July 11, 2010
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