Doing something stupid, crazy, and/or disgusting.
There are three rules to bladding.
1. You must bring someone who's never bladded before
2. Once you agree to go bladding, you can't back out. Bad things happen if you do.
3. You can't talk about bladding to anybody.
Guy1: Hey, what's bladding? I Googled it and nothing turned up.
Guy2: I can't tell you, it's secret. But if you want, you can go bladding with me and some other guys and you'll find out yourself.