epfidemic:

Your daily dose of Sexual Positions - Knees to Chest

Enter her as you would in the standard missionary position, but instead of simply spreading her legs, have her lift her knees to her chest and hook her ankles over your shoulders. Support your weight on your hands. This gives you greater penetration and stimulates the back walls of her vagina. 

epfidemic:

Your daily dose of Sexual Positions - Reverse Cowgirl

When she’s on top, encourage her to turn around and face away from you. This creates G-spot stimulation for her, and the change will help you hold out longer. 

epfidemic:

Your daily dose of Sexual Positions - Downward Dog

Have her lie facedown on the bed with her hips raised. (Use a pillow to allow her to last longer.) Entering her from behind, you’ll be able to thrust deeper and hit the hard-to-reach pleasure zones just behind her vagina.