I see tons of girls on the internet that are taking whole arms,fist's,and even a mans head!I don't think a cock will be able to phase most girls during sex soon,we'll all be out of work.
Sufficient length is good so you can confortably do different positions without the penis popping out a lot plus the stroke is longer which keeps our stimulation more continuous. But clearly thickness is the more important dimension.
what's wierd is a lot od sex toys (dildos/vibrators) are really thin like the thickness of one finger, perhaps women would prefer it if a mans weiner could vibrate at 1000rpm lol