I'm 20 and have been masturbating pretty regularly since I was 13 or 14, so sex and orgasms are nothing new for me. For various reasons (including a septate hymen that is still intact), penetration has never been a significant part of my sexual activities, both solo and with others. I've found my g-spot before, but that only makes things marginally more intense -- it isn't as amazing as it's usually described. Even when it isn't painful, penetration doesn't seem to do much for me -- in fact, I can count the number of times I've orgasmed while being penetrated on one hand. (heh)
Today, for the first time, my partner was able to make me orgasm while penetrating me (one finger) -- this was the first time it's ever happened with someone who wasn't me. The orgasm didn't feel different from orgasms I have from clitoral stimulation alone, which was also involved today. Afterwards, we discussed how my vaginal walls don't tighten and spasm as seems typical (both based on our sexual experiences and what we know of others') -- in fact, if whether I was orgasming was based solely off of what was going on in my vagina, there would be no way to tell. I had observed this previously while masturbating, but thought that it might be different with someone else involved.
So, vagpag -- has anyone else noticed something similar? I'm not terribly worried about it, but I'm rather curious -- surely, there must be a reason out there somewhere!
ETA: Another thought -- I Kegel a few times a week and use a Diva Cup, so I know that my Kegels function and such.