Trunking or the act of Trunking is when one person gets in the trunk of a car, and at the right moment, pops out and scares/surprises the nearest people. Trunking usually occurs in parking lots at parked spaces, however can be done anywhere. The main goal of Trunking is not to harm, or scare, rather than to observe the reactions people will give you!
Tim: OMG LETS GO PLANKING!
Mike: No bro, trunking people is better, its the newest trend.
Tim: Oh I saw that shit! Lets do it!
Mike: Hell yeah.