This idiom or expression has to do with:

Making someone angry by touching on a subject that bothers them. (Could be intentional or unintentional.)

Q. Why can’t the two of you get along?
A. I don’t know! Somehow he always manages to push my buttons. I don’t like that.

Also: Pressing someone’s buttons.

Compare to: Get one’s goat.

Also means turning someone on sexually.

Q. You like her, don’t you?
A. Yes I do. She knows how to push my buttons, and I like that.