Wiktionary
whip the pants off
vb. (alternative form of beat the pants off English)
Usage examples of "whip the pants off".
I'm going to give you the fight of your life, whip the pants off you, and wipe that know-it-all look off your face!
I'm going to give you the fight of your life, whip the pants off you, and wipe that know - it - all look off your face!