I wanted to see how many big guys have experienced not being able to give their wife or gf friend an orgasm from just penetration alone? I'm an avg 6" guy a good thickness who has tried with several woman and felt I was unsuccessful giving them an O. My current girlfriend no matter what position cannot get one, for the exception of her being on top and griding her clit into my pubic bone. Makes one feel like less a man. I was going to ask her if she had orgasms at all from other men she dated that were bigger then me from penetration only.
You have already heard some great advice and thoughts, so I'll try to cover some other considerations.
You need to consider that one of the more successful and popular women's simulators is much much less than your 6 inches.
You (We) need to consider that the most sensitive nerve endings are not that far into a woman's vagina. Basically inside and across from her clitoris. If you truly want your woman to orgasm from penetration, that's the area to concentrate on.Before I understood that,it used to be sort of a game with me to grasp my cock at the base and only use the remaining three inches or so to penetrate her. What I didn't fully understand at the time was how much stimulation she received from my erect head in that exact spot.
That's not to say that women can't have an orgasm from thick, deep penetration. But in my estimation that goes more to the mental side of female arousal than purely physical.
Many women find deep penetration uncomfortable enough that they cannot mentally engage in the sexual act. Though someone on the larger side may still find them a willing partner for that penetration, it often takes them some time to physically warm up and mentally consider the implications. I had one woman tell me that she was exceedingly stimulated mentally when I only penetrated her with the portion of my cock. Her eyes saw what I still had in "reserve", and her thought was, if it feels this good now, how will it feel when he's balls deep. She could orgasm not just from the physical stimulation along that most sensitive area, but from the mental image of being opened up from deeper penetration. I think that is what truly drives the orgasms for the women with a size preference, it's primarily from the mental image they conjure up.
I don't know how many others of you sort of "warm up" your partners the way I do, but it's truly a great feeling when she's extremely aroused, then you slide that next inch deeper. You usually get some verbal acknowledgement of pleasure, if she's able to keep her eyes open you might see surprise or some fluttering, in my wife's case I always get an extra squirt of wetness that tells me that she's enjoying it.
So take it from me, bigger, deeper, isn't a cure all. If you have 6 inches, you have more than enough to satisfy almost any woman. It comes down to technique as well as mental and physical stimulation. Going balls deep doggy style (especially too soon) and unmercifully pounding her cervix is only going to arouse the truly twisted ones.