When a woman is not wearing a bra, she is said to have 'wild boobies'. Often this is present before a female goes to bed or after she has engaged in sexual intercourse. The verb freeboobing is a synonym for this phenomenon.
2 Girls at sleepover:
Girl 1: It's getting late, time for wild boobies.
Girl 2: Yeah this bra is uncomfortable, I'm about to have wild boobies as well.