This guy I just started seeing is a pretty awful kisser. How do I deal with that?

We've only kissed a couple of times, but he seems pretty inexperienced. He shoves his tongue in my mouth aggressively, (and, bizarrely, gropes my *** INSIDE my jeans). It's just sort of weird, but I absolutely can't imagine stopping him and telling him to please chill out with the tongue. What should I do?