Im 6" and my girlfriend is so small she has trouble taking me, the first few minutes of sex have to be very delicate until she stretches a bit and the endorphines kill the pain.

It literally depends on the woman, some like huge pornstar ***** and other like large (7-8ish) and some prefer average ones (5-7ish) and some can prefer smaller ones (4-5ish). It depends on what they can handle because women have different size and tightness of vagina as men have different penis size.

Also size isnt as important as people seem to think, granted under 4inches isnt going to do much at all and over 9inches is likely to be uncomfortable for 80% of women but generally the to reach a womans deep spot and easily the g-spot the guy only really needs to be about 4 1/2-5inches, other than that almost any guy can give a woman amazing orgasms and sex with good technique... most orgasms happen before intercourse even takes place.