riding the cotton pony 

having a period; menstruating.

better put a plastic sheet on the sofa before thunderthighs sits down, she's riding the cotton pony.

riding the cotton pony by Dunky Oggins November 23, 2003

riding the cotton pony 

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.

riding the cotton pony by damedonna July 3, 2006

Riding the cotton pony 

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."

Riding the cotton pony by Spaceman564 January 19, 2012

Elmo Riding the Cotton Pony

Menstrual cycle, period, time of month

a phase of the menstrual cycle in which the uterine lining is shed

Woman: No fun tonight

Man: Why?

Woman: Because Elmo Riding the Cotton Pony

Man: :(, I guess I just use this sock instead

Elmo Riding the Cotton Pony by KMT83 December 24, 2011