What does "lick it up" mean in this context?

The following is from the TV show The Big C.

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Cathy: You're late again, Andrea.

Andrea: Yeah, but I figured since you usually spend the first ten minutesof every class trying to get to your point, I didn't miss a whole lot. "Class, chapter one. Ooh. Sorry, chapter two. Sorry. Sorry. Sorry."

Cathy: Funny. Come get your test. You can't be fat and mean, Andrea.

Andrea: What?

Cathy: You heard me. If you're gonna dish it out, you got to be able to lick it up. Fat people are jolly for a reason. Fat repels people, but joy attracts them. I know everyone's laughing at your cruel jokes, but nobody's inviting you to the prom.

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Andrea(student) makes fun of Cathy(teacher) during class, and Cathy

is kinda upset. Could you please explain what "lick it up" mean in this

context?