When you go down on a girl, usually of teenage or early twenties, for so long that her vagina, specifically her clitoris, becomes so sore, it turns purple, making her feel as though, it will burst. Surgical bursting will become necessary
Fred: He gave her a Purple Starburst?!?!?! NO WAY!
Bear: Yeah, no shi* bra, she had to go to I.C.U.