Free balling is a colloquialism for which I have run into two meanings. Both definitions revolve around the common theme of uninhibited genitals.

Definition 1: as a male, to walk around nude. Thus, not only your balls, but your whole package is "free". Also see naked, nudism.

Definition 2: as a male, to go without underwear. The man still wears pants and the rest of his clothes, but is free to move around under them. Also referred to as "going commando" as popularized by Joey in "Friends" and Cosmo Kramer in "Seinfeld."

note: this was a nodeshell rescue