He won’t leave my ass alone

So the last couple of times my boyfriend and I have been intimate he’s tried rubbing and fingering my booty hole. I keep telling him I don’t like it and he says okay I’ll stop but a few minutes later he’s doing it again. He also has ate my ass without asking or telling me he was going to several times and I just do not like it. He also asked me to eat his ass but I’m not into it. How do I get him to stop? I’m just fed up because I want sex but I dread it because I know he’s going to pull some sneaky shit like that.