to stake out or case a clothing store's dressing room, waiting for somebody to sling their pants over a partition wall in hopes of grabbing the pair, hastily sliding them on over your own and running about before eventually abandoning the pants at an undisclosed location.
"dude, i was like trying on some slacks at AE when some douche grabbed my dockers and went joy-pantsing. it bummed me out. where the popped collars at?"
What many high school students will do to fellow classmates if they decide to wear sweatpants. It is far to easy to catch the wearer of the sweatpants off-guard and pull their sweats down. Any other form of clothing on the bottom is not to be messed with.....only sweatpants.
Poor girl decided to wear her sweatstoday; she's probly going to get......oh, and the pantsing begins.
When you come up behind someone and pants them then when they bend down to pick up their pants you step on their pants and give them a wedgie. If done right you should have wedgied your victim right out of his pants. If you want to be really mean you can duck tape his hand and blindfold your victim while you hide his/her pants/shorts so afterword they have to find their pants in their underwear.
One time at camp a bully came up behind he and pantsed he then gave me a pantsing wedgie.