Originally Posted by PurpleOnion
It makes sense that the actual penis doesn't actually increase in size larger than it already is but that the erection is just fuller.
That's exactly the way it works...at least for me. If I put on a hot porn video, my cock responds by plumping up nicely, stretching forward nearly full length, but not exactly tight. But if I take a tab of viagra and watch the same video, my cock rises to the occasion with a rock hard erection, stretched to maximum, with the shaft skin taut and almost shiny, and the head swells to a firm knob. It's in perfect condition to use as long as I want, until I let go with my load.