Houdini of the Beach

A forbidden technique for changing into a bathing suit passed down from father to son. Without proper practice, using this ancient art may result in dire and painful consequences.
It is performed as follows:

Remove pants, then wear your suit over your underpants, then, remove underpants out from under suit.

Guy 1: Finally here at the beach, let's head over to the changing rooms and get ready for a swim.
Guy 2: Nah bro, you go ahead, I'll just get changed here using Houdini of the Beach.
Guy 1: You can't be serious! What if it goes wrong?!
Guy 2: Trust me, I got this! *Tries it and immediately rips underpants* ... Fuck.