You have to T Bag them after you kill them… This is the truth. I did it the other day.
Stand over the freshly killed corpse, pull your own pants down and squat, stand, squat, stand and you will get it. Essentially, you are teabagging them.
this challenge is a little screwed TBH yes you have to teabag the enemy but what i have noticed is that the game is a little screwed in this process,
i killed a enemy he dropped a blue case (YAY) and i picked it up "humiliate enemy" i teabagged the enemy i got the blue case from and got it which is a little screwed cause it said the next enemy you kill humiliate them