Bizarre fingers

This guy I was intimate with asks to finger me and he just jams his finger in. It was so uncomfortable that I couldn't get out another sound. He thinks it was an orgasm. I told him I don't like it. The sex actually is pretty bad too. Well, I'm not pleased how he does things. I've tried to teach him what to do. But he's taking tips from the Hub. I appreciate his effort to learn. I like everything about him but the sex. Is there ever a way to end it because of sex? I think we can work it out but the jamming of the fingers has to stop. My vagina is not happy these days about it.