What's the average penis size?

About 5-6 inches: On average the erect penis is about 5 -6 inches long. Like most things in life the size of a penis in a population follows a bell shaped curve. The vast majority are in the middle and a few are on the low side and a few are on the high side. Also the unerect size doesn't always correlate with the erect size. Sometimes good things come in small packages.

Hard to say: I mean, difficult. Depend on how you come about measuring. Don't know if that is the right question anyway. Maximum sex is achieved long before the bedroom, more like what happens in the kitchen is what matters most. A smile & kind word, a soft glance, relieving her stress, better grooming, the right scent, helping with dishes/house chores, non-sexual touch hours before, look long into her eyes