When a female, usually large breasted, intentionally or unintentionally wears a bra with a cup size larger than her own breasts. This effect will become teasingly apparent when coupled with the low cut and/or sleeveless blouse, spaghetti strap top or summer dress. As a witness to this undercupping effect, one will have the opportunity to witness top boob and possibly side boob depending on how a woman positions herself and her breasts fail to entirely fill her bra cups and thus remain exposed to the extent that the bra allows.
1. My friend and I were in the downtown park yesterday at lunchtime and were the happy witnesses to some great undercupping action as the women sat to eat their lunch or bent down to "check" their shoes in front of us.
2. While I was on the treadmill last Thursday I couldn't help but notice the serious undercupping action going on with the girl immediately to my left as she bounced and bobbed on her machine.