lay right next to her so you can kiss her and look her in the eyes.
make her really fucking wet, do slow at the beginning and pull your middlefinger inside really slow. When you are completely inside her, rub your finger up to the direction of her stomach, like if you lure someone with your finger. If you are lucky you can feel a spot which is more abrasive , this is the G-Spot. With the other hand you can rub her clit nice and slow.
I made my ex-gf cum 5 times in a row like that. hfgl