It's been a couple weeks since this thread was active, but thought I'd chime in since I do appear to be in the SPH/SDH minority here.
(And actually, I am kind of suprised I'm a minority, because the mytinydick.com content seems to be SPH-slanted.)
Even though I didn't actively seek out SPH/SDH or even really think about it in my adult life until I discovered mytinydick.com, there are roots of it that stretch back way in my past. There were a couple of women I knew (friends' moms) when I was in junior high that I had these fantasies about where they would disapprovingly watch me masturbate and never touch me. I was just a boy, of course, so ALL of me was small back then. I think the fantasies were just my way of working out that even though I was attracted to them, there was no reasonable way I'd even have intimate contact with them... so I constructed a fantasy where I could get aroused, but didn't do anything impossible. (I've never been able to fantasize about celebrities or women I don't know... it's always been women in my life, and I think it's because the fantasy only works if it seems like something that could really happen.)
There's one other thing, though. In my day-to-day life I am dominant. I make decisions when others can't decide; I always guide things when I'm with my friends, and I seem to attract submissive women. I've never dated/married a woman who was even slightly dominant. So I think that the SPH for me is a chance for me to sort of retire from being the leader all the time and kind of be put back in my place. It gives me some balance.
And in practice, all these women I fool around with on the side... the SPH is just a little bit of roleplay we do up-front. It loosens me up, but we transition into normal x-rated lovin' pretty quickly, and it's always been mutually respectful.