What do I think about it? Weird, gross, but inoffensive so to each their own. I don’t think they want to go back to their childhood, but perhaps they want to relive that sense of powerlessness. It’s like the ultimate submission.
Intrigued by the difference between “fetish” and “hobby,” I looked them up in the dictionary.
Fetish (in this context) is defined as: “an object or bodily part whose real or fantasized presence is psychologically necessary for sexual gratification and that is an object of fixation in that it may interfere with complete sexual expression” (m-w).
Adult babies are about role-playing, scenario and actions, not objects. Certain objects may be included, even necessarily for some people (diaper, bottle, toys, etc.), but these are props: they’re not the main focus of the fixation.
Hobby is defined as: “a pursuit outside one’s regular occupation engaged in especially for relaxation” (m-w), “an activity that one enjoys doing in one’s spare time” (wikitionary), “an activity or interest pursued for pleasure or relaxation and not as a main occupation” (ask).
It’s not like being an adult baby wouldn’t count as a hobby under these definitions, but I don’t think the fit is right. I mean under these definitions, any sex (other than sex work) would count as a hobby. It’s too vague. Yes, it’s a hobby, but what else is it? I think we can do better. What about a kink?
Kink: “an unconventional sexual taste or behaviour” (m-w).
