The argument of "size doesn't matter, it's what you do with it" is true if you're blessed with a partner, whom is gifted in skill; but as new research shows, on the contrary, "size does matter" for some women, and for certain types of orgasms.
A new Evolutionary Theory of Vaginal Orgasm published in the September 2012 edition of the Journal of Sexual Medicine sheds new insight into the idea that women who prefer longer penises actually experience greater frequency of vaginal orgasms from penetration, not to be confused with clitoral orgasms.
However, as research indicates, many women find that penis size is important, a woman's orgasm during penile-vaginal intercourse (PVI) is influenced by fitness-related male partner characteristics, and a woman's preference for a longer penis is associated with greater vaginal orgasm consistency; the latter being triggered by PVI without any clitoral stimulation - having a vaginal orgasm the old-fashion way.
Researchers found that women who prefer deeper penile-vaginal stimulation are more likely to have vaginal orgasms, consistent with the Evolutionary Theory that vaginal orgasms evolved as part of a female mate choice system, favouring somewhat larger than average penises.
Researchers also found that the likelihood of vaginal orgasms with a longer penis was related to greater importance attributed to PVI and lesser importance attributed to noncoital sex (any form of sexual activity that does not include vaginal penetration).
The data from this specific study was from a limited group of Scottish university students, so until the study is replicated amongst a broader group, one can only deduce that a group of Scottish women prefer longer penises.
Finding sexual satisfaction is an intimate art between you and your partner. Perhaps a longer penis will be able to stimulate more areas of the vagina, and maybe not. The point is one needs to be in-tune with their body and be able to communicate that to their partner. There's no rocket science here but a classic case of trial-and-error, and opening yourself to new experiences.
Journal Source: Costa RM, Miller GF, and Brody B. Women who prefer longer penises are more likely to have vaginal orgasms (but not clitoral orgasms): Implications for an evolutionary theory of vaginal orgasm. J Sex Med 24 SEP 2012