What will it do:

thickens the penis, providing additional girth; also strengthens the erection

forces blood into the already erect penis, expanding the inner chambers and thereby allowing for a larger erection

Your penis must be almost fully erect. Lie down flat on your back or stand upright. Part your legs slightly.

Stimulate yourself to a nearly full erection. For a little help, look at her or him or them.

Make a circle with your thumb and index finger. Wrap that circle around the base of your nearly-erect penis.

Flex your PC muscle (see Squeeze exercise) hard; this forces even more blood into the penis and makes it even thicker and harder. Grip your penis tightly at the base with your thumb and index finger, trapping all the blood inside the penis.

Your penis should look and feel quite full and erect at this point. The skin of the head might be pulled very tight and appear shiny. Small and large veins might appear on the shaft.

You can also do this exercise with two hands, squeezing tightly at the base of the penis with thumbs on top and fingertips on the bottom.

Hold this position for ten seconds at first. Then relax, switch hands, and repeat.

Alternate grip: Use an underhand grip instead, still clamping your thumb and index finger around the very base of the penis. This time, though, the rest of your hand is underneath the penis holding your testicles.

Squeeze the penis tightly for ten seconds with each hand, repeating twice with each hand. Each day, add five or ten more seconds to each repetition.

Increase until you can do a full minute with each hand, and do five full repetitions.

As you increase the duration of the repetitions, you'll want to "refresh" the blood source inside the penis. To do this, briefly relax your grip. At the same time, flex your PC muscle hard. This allows extra blood to flow into the penis and expands the tissues even more. Immediately tighten the grip with your hand.

For added benefit, put your knees together and tighten your buttocks muscles. You will feel additional pressure in your erect penis as you do this. Try this technique during the last ten seconds of each repetition.

I do this one first thing in the morning with that first great erection of the day, usually after a few minutes of the Inflation exercise.

This exercise can also be quite useful during foreplay. I sometimes do one or two repetitions of this exercise once I have an erection and before engaging in intercourse. The exercise can add up to 1 cm of circumference to the penis, which can be quite noticeable to your partner in the right circumstances.

This is the one exercise to which I attribute most of the gains I have achieved. After doing this exercise for up to five minutes a day, my penis feels much thicker and heavier than ever before.

The effects of this exercise are similar to using a vacuum pump. See What Doesn't Work.