Lie down on your side and hold onto your penis with the Backhand grip. Roll over further and brace your hand against the bed, and thrust your penis in and out of your hand. This closely mimics the movements of intercourse. It's a very different feeling to masturbate by moving your pelvis rather than your hand. It's also fun to put your other hand down and feel your scrotum moving back and forth as you pump in and out of the "vagina."
If you like the "Vagina" technique but don't have a lot of stamina or energy, masturbate normally until you can feel that if you don't stop, you'll ejaculate. At that point, wrap both hands around your penis and start pumping "Vagina"-style like there's no tomorrow. This will be a very rewarding experience.
Kneel on the floor, and lay down a towel. Lube up well, and lock together the fingers of both hands, palms up. Place your erection in your hands, and wrap your hands around your penis. Then put your hands (and your erection) on the floor, and pump your pelvis front to back, without moving your hands. Throw your head back, close your eyes, and imagine having sex with the girl of your dreams. You may have to lube up a few times, but it produces a very nice orgasm.