As you are masturbating with one hand, place the fingers of your other hand just below your navel and apply a good bit of pressure (but not so much that it's uncomfortable), and while pressing down, slide your hand down to the top of your pubic hair. Keep repeating the process all the way through orgasm – don't stop as you approach ejaculation. This will give you an incredible feeling during your orgasm. Warning: Don't press too hard, or for too long – you could cut off circulation to your legs, which could be dangerous.
NAVEL-PRESS EXTENSION
Use the Navel Press technique until you sense the coming orgasm. Now, still applying pressure, draw the "navel hand" all the way up the center of your abdomen (even up to your chest if desired) and then down again. Do so until ejaculation. This technique harnesses the powerful feelings produced by the Navel Press, carrying it throughout the torso. It also simulates contact with a female on top. (You might try to envision that while performing this technique.) You might try sliding more lightly while ascending toward the chest, applying more pressure while descending toward the penis, with maximum pressure at the navel area.