Then notice how nice it feels with the Progasm's head just inside. Keep pressing lightly, or use anal contractions to draw the head to your inner sphincter. Contact there will give you a bit of a buzz. Imagine the inner sphincter pulling it through and it will.

Once through, you can comfortably slide the Progasm in deep. Press the P- and K-tabs firmly to your flesh and notice any buzz you feel.

Then engage the plug to your prostate. My preferred way of doing this (with any Aneros plug) is to take a leak; that automatically engages the PC muscle and outer sphincter. The slight feeling of congestion while pissing is a sure sign of prostate contact. Afterward, it should feel real good. Involuntaries often start up.

I usually take engagement up a notch by stroking my cock - 20-50 strokes until I'm fairly hard. The engagement is strong at that point and involuntaries are bound to start up. After that, I let the Aneros do its thing.