Last time I saw her mom I was so rude towards her.
Were you really? What did you say to her?
I told her that her son's dick sucked.
It's inappropriate to use vulgar language when describing a child to their parents as it can be very emotionally hurtful. Instead of trying to get a rise out of that parent you should refrain from using coarse language and instead work out whatever issue that has come up between you and that person. Needlessly antagonizing a parent will damage your reputation as well your family's.
I don't care. She's just a bitch.
People will start to think negatively of you if you continue such behavior, why don't you try to sort out your differences? You may have a lot more in common than you think, and all of this can be put past you.