Playing in the mud is a remedy, common in Northern California, for making a woman's vagina feel tighter, especially after its been stretched out by a large penis. To play in the mud is to first get a woman hot and bothered followed by her stretching her vagina so that you may defecate in it. Once the feces is inside you then proceed to have sex with the vagina enjoying the extra tightness brought about by all the fecal matter inside.
Parker: Wow Ryan, that chick Bjorn hooked up with sure has a flappy vagina!
Ryan: Yeah i know i bet its so wide that they cant even have sex!
Parker: Well they could always play in the mud.
Ryan: Yeah, i suppose...
when a woman won't let you have sex with her because she is on her period or when you don't want period blood all over your penis, you have anal sex instead.
Guy: "let me smash that vag"
Girl: "I would let you, but i'm on my period"
Guy: "if there's blood, play in the mud !!!!!"
If somebody says "if there is grass on the field play ball" but there is no grass on the field a response is "if not, then flip her over and play in the mud."