When I was younger there used to be a legitimate thirst, lust, hunger, to have a woman's tits in my mouth and suck them. This would be a build up after seeing them either in public or dressed up. Seeing on TV included
Even random brushing up against them while in school or privately getting a chance to feel on them through the fabric. I'd imagine every second with me licking them or sucking nipples would increase my arousal ten fold. This was when I was younger, without knowledge of the hobby, and the anticipation for sexual contact with a woman was more electric than a transformer box near a power line. If I'm getting a crazy erection at just the sight of some firm tits bouncing up and down through a dress or a blouse, why can't the experience translate to scale when I'm BCD today?
My experience with sucking tits today: (mostly/exclusively now in the hobby) It doesn't bring that increased sense of sexual arousal. I'm already arouse and although I want to put the nipples in my mouth, and do, it's not sending electric pulses to the rest of my body and getting me stiffer. Because I already know she's getting naked, even floreplay of rubbing on her tits and eventually sucking them doesn't create a strong build.
Don't get me wrong I'll still do it and like to do it. But these days I'm doing it just for the woman's pleasure.
And this came to my mind after seeing this well endowed provider's ad - http://eccie.net/showthread.php?t=1334262