Free clam 

When a female neglects or chooses not to wear panties for any number of reasons

Girl, that skirt was so tight, I had to free clam just to avoid panty lines.

Free clam by humminbird July 6, 2010

free clam 

A woman "going commando", or the female's version of "freeballing."

Oops, she did it again - apparently Britney decided to free clam that day and gave the photogs another free show.

free clam by Kinaya March 29, 2009

Freeclaming 

Going without panties, said of a female, so called because her pussy (aka clam) is free and unencumbered. A similar expression is "going commando," which can be used of either a male or female without underwear, but is more often used of a male.

"Freeclaming: A lot of girls like to secretly freeclam in the summer, but those who are caught are labeled a slut forever"

Freeclaming by Muff divah October 13, 2011

Freeclamming

When a female is not wearing any underwear under her clothes; as in, the equivalent of the male "freeballing".

Jenny decided not to wear underwear today. Her friend Jane asks: "Jenny are you Freeclamming again today?"

"Hellz yeah I'm Clamwagging today, I'm really Clamflapping and Clamcasting. I'm clamskipping my clam all over town.

Freeclamming by Lokidyonysos January 27, 2011