He spanks me a lot and he'll grab my ass a lot. I'm pretty sure he does it in a jokingly way but its annoying and makes me feel kinda uncomfortable. I tell him to stop and he says he will but he never does. It drives me crazy.
Talk to your mother and enlist her support and help in this. Maybe your Dad will listen to her. Good luck and let us know how this goes.
I would be talking to your father first and letting him know that it makes you feel uncomfortable before you talk to your Mum.
