This thread's fascinating to me, about the deep psychology of fetishes. Here's why.
My ex-wife and I did all kinds of breast play through all the years we were together, including suckling, often with bits of playful little boy role play, and it included all kinds of "adult breastfeeding" during the several years we had nursing babies. We did it for both of our pleasure; to reduce engorgement when she was in discomfort; to celebrate her pregnant and nursing body; as play; and just because we totally loved each other and our babies. She's almost comically well-endowed in the breast department, she was born to breastfeed. She may yet get a breast reduction for her own health and comfort, she explored the possibility for a long time.
And ... I never thought anything of it. I'm serious. It became a normal part of our foreplay almost from when our relationship started. The idea that this is far out and weird to some people here ... well, I'm not challenging your right to have your view, but it just never crossed my mind.
I think this "not even thinking about it, just feeling good while playfully doing it" about exploring each others' bodies was what sex was meant to be. The revelation in this thread for me is that here's something that's a dream for some people and a weird taboo for others, and I just had it for a big part of my adult life.
Whereas the pee thing -- well, that was tough between us. She listened with compassion when I told her about it, and she did it sometimes for the first few years, but not happily. And when I left her (after 17 years, for reasons that have nothing to do with any of this), she was really bitter about having been part of it. And I don't think that had to be. I think the difference was exactly this, and nothing more: I was hugely afraid of and ashamed of the pee and/or diaper thing myself. (I still am.) Telling her was one of the most terrifying things I ever did in my life. And I didn't (and don't) have a hint of fear, shame or obsession about cuddling up and sucking milk from her breasts -- for real, during the baby years (and yes, that's very nice), and in play before and after.
I truly believe we both, together, could have found that same kind of innocent shared pleasure, fun, laughter, exploration and sensual joy in our own and each other's bodies with pee or any other thing we tried, if not for the shame and fear I felt about it.
I'm pretty convinced I developed a pee and diaper association with sexuality completely by accident, for reasons that are laughably random and not my or anyone else's fault. I was a little kid. Any number of other things might have happened instead just as easily. But I had deep shame about wetting, mixed with sexual attraction to it. That was poison. I tainted it for her, with years of my own feelings, before we ever did it.
And meanwhile the same two people, she and I, could lie there with me playing baby at her breasts, mostly at her initiation, and her rubbing me to orgasm through my pants and making jokes about liking it when her baby was wet.