Squiflop is the sound which the "Killer Boobs From Hell" make when they escape from that Russ Meyers movie and come bouncing down the street to attack and destroy you.
Similar to or related to a wedgie but involving the anterior aspect of the underpants. A swift upward tugging motion of the frontal drawers. Typically evolves into an exaggerated amount of pain to the phallus, yam bag, or fur-burger depending on the gender in which the act is performed.