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when a woman is on her period.
"Why is she being such a bitch today?"
"I'm not sure, maybe she's riding the cotton pony."
by Spaceman564 January 13, 2012
having a period; menstruating.
better put a plastic sheet on the sofa before thunderthighs sits down, she's riding the cotton pony.
by Dunky Oggins November 23, 2003
A term used to for a female having a period. It references using a tampon (the cotton pony).
I had cramps all day because I'm riding the cotton pony.
by damedonna July 03, 2006