when you are wearing some sort of underwear (boxers, briefs, tighty whities, thongs ect.) and pulls it very high so it rides up your butt crack. or in the front squishing a guys balls (also called penis, nuts, ect.) this is painful and most people love it. try giving yourself a wedgie at home or somthing while your alone!
my friends spent the night for the entire weekend and well of course i fell asleep first and well they put my hand in water and when i woke up i was in a hanging wedgie (where your underwear is on somthing that lifts you up off the ground completely) and scince if your hand is soaked in water while you sleep i was peeing myself the entire time in that major wedgie!