US, informal: to yank down the pants of (someone) as a prank or joke
Sandler plays Dave Buznik, a Brooklyn-born wimp, a patsy, a schlemiel so mild-mannered he makes other people want to pants him. Lisa Schwarzbaum
"I was standing on the corner with my friends and we saw some girls we knew from school," recalled Robert Alicea … "They were walking past when my friend decided it would be funny to pants me. The girls started yelling and pointing—it was horrible!" Greg Downing
Phrases
with one's pants down
US, informal
: in an embarrassing position (as of being unprepared to act)