My boyfriend hurts me when he rubs my clit...

So I’ve been sexually active with my boyfriend for about a month now. He’s good but I haven’t had an orgasm yet. He’s good at fingering me and all but just when it comes to rubbing my clit he does it too hard and it isn’t on the right spot and it hurts. How do I tell him politely that it isn’t a pleasurable experience and how do I teach him how to do it?