I agree with Maven that masturbation is the best way to find out the details about what, where, when, how hard, etc. Maybe he even watches you and rubs your thighs or plays with your breasts while you do it. That's very sexy and a great learning experience for him. In this age of empowered women, you can also take things into your own hands (literally). Go cowgirl, and while you're riding into the sunset, reach down and give your clit all the massaging it needs just the way you like it.

In general, it takes 2 people to tango. Just explain to him that he is not "giving you an orgasm". You are working towards your orgasms together. That's why sex is best/easiest between 2 committed, loving people. Ultimately, if you can't have an orgasm from intercourse, just get close and then move on to the next thing. Oral is always a very welcome choice for the ladies.

This all takes trust and communication. I tell my older teen kids that if you can't talk in detail about sex with your partner, you shouldn't be having it.