rag on (one)
1. To nag, criticize, or berate one, especially at length. I wish you'd quit ragging on me—I told you I was sorry! The boss started ragging on Thomas in front of the whole office for messing up the Roberston accounts.
2. To tease or mock one. My friends are always ragging on me for wearing a backpack that has My Little Pony on it. We rag on each other constantly, but it's all in good fun.