1. Performing perverse sexual acts of depravity on store mannequins with a heightened sense of arousal from being caught.
2. A form of exhibitionism.
3. Similar to Ellen DeGeneres' Dance Dare which involves dancing behind peoples backs, mannequink entails standing next to an unsuspecting shopper and waiting for them to turn around. When they do, you vigorously grope and make out with the mannequin next to them for 5 seconds, then turn around like nothing happened before they notice.