bag on (one)
1. To judge or criticize one. Why are you bagging on me? I didn't do anything wrong! If my friends see me with this stupid haircut, they'll bag on me for months!
2. To tease one. Ugh, my brothers always bag on me when my mom's not around. It's so annoying.
bag on someone
Sl. to criticize someone. Stop bagging on me! I'm tired of all your complaining. If you are going to bag on everyone all the time, I don't want to hear about it.