Frog gigging?

Please help to find an idiom with the following meaning: when you knowingly do\tell someone something, that he does not like. For example strike a cat against its fur (everybody knows that cats don't like it)

"Be the bearer of bad news."

But do you mean who tells bad news or says something for sport, to annoy the listener? I had a coworker who recently said, "I gigged her." (As in frog gigging.) She meant she deliberately said something to "get the other person's goat." Another idiom.

Frog gigging?
Never heard that in Brooklyn
I give up.

I never heard of it in NY, either, growing up. I had to move to the Midwest to learn about it. To "gig" a frog, one uses a pointed spear (a gig, as it happens) and ... oh, I can't go on. It's just all too brutal.

I didn't hear about it until I moved to Kentucky. Frog legs anyone?

Do frogs legs go with grits?