like B&D i am not a big believer in erotic attitudes. and i hate the word infantile too. who would want to connect sex w infantile. it brings forth images of, yes daddy do it to me or some fucked up shit like that.
if i try to understand it, what i understand is that the so called infantile has Si in the superid block. esp with the dual seeking function, people tend to be child like, no matter what information element is found there. the person has this glowing i'm-not-worthy respect for persons with that information element in the leading position.
so if you are infantile you value Si but you can't really do it. so Si amongst other things is about internal sensations and balance. so if the person isn't that good at that, but admires it, it kind of places them in awe of anybody who can safely make their insides feel good. the keys are safe and feel good.
the kind of person who can do this is somebody with Si in their ego block. somebody who is a master of sensations and who makes people feel safe. by way of contrast, theoretically, somebody with Se in the ego block wouldn't feel safe to the infantile person. somebody with Ni theoretically would be in a neutral position. another infantile would feel like the blind leading the blind.
so i guess all in all feeling sexually safe is important to infantiles. and getting with somebody who really knows the body and what makes it feel good.
having said all that, i wonder if this doesn't apply to everybody. or not. maybe Se/Ni people like a lack of safety, that's a turn on to them.