Both a statement and a question pertaining to a woman's menstral cycle. It refers to the possession, or need, of a tampon (cotton) during a woman's period. Phrase made popular by Megan Fox in the movie, Jennifer's Body.
(statement)
Nicholas: Hey Selina, you look bloated today!!
Selina: Yea, I'm definately packing cotton today.

(question)
Hey girl! You're being a real bitch today...you packing cotton or what?!
by Irishman1973 August 25, 2010
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