When you stick your arms out in front of you as if you were
dirtbiking, then pretend to ride a dirtbike by running around and making loud and obnoxious dirtbike sounds at the top of your lungs in a public area. May be accompanied by dirtbike gear. Usually, a bout of
dirt biking is accompanied by wipe-outs, where you do a spectacular crash and make
sputtering sounds. Afterwards, you can pick up the bike and do a sweet wheelie to get out of there.
Example:
Guy 1: Man, did you see that
plank I did?
Guy 2: Planking? Everyone knows
dirt biking is
where it's at!
Guy 3: Ya, I just went dirt biking in Wal-Mart!