Go to the site's Home Page and look at the sexual positions for Woman Superior/Cowgirl.

The woman is generally in control when she is on top. This is especially true when the clothes come off, and/or it is your first time or two or three.

In addition to DD2's comment: Bonus when dry humping would be you don't have to concern so much about connecting pelvises the right way (like you would when having intercourse). You can also just lie on top of him flat on your tummy or your back and curve and twist your body just a little bit (anything he's comfortable with since you'll be pressing down on him). Though he's under you, you can give him a bit more control touching you. On your back on top of him can be quite overwhelming; he can kiss your neck as well as touch your entire body with easy access. If his erection starts to kick in all the way and gets uncomfortable to him, you can open your legs a bit and let it "peak" through your inner thighs. This provides for some nice opportunities as well; any movement you make could be very exciting for him. Just be aware that the dry humping could get a bit more wet. Should he ejaculate, you should prevent leaking through his and your clothing! Only one sperm at the wrong place at the wrong time is needed to get you pregnant. So be aware of what you both are wearing beforehand.

At the risk of sounding like quagmire from "Family Guy"...
GIGGITY