Again though, I don't think it's sexual. It's not about sex itself, but about intimate relationships.

Ne types are "child-like" simply because of their Ne, and this "child-like" quality is a matter of how they generally behave. Inside a relationship with a Si type, they are cared for by that Si type. The Si type is attracted to their child-like wonder and perspective, and they like that the Ne type appreciates that they care for their comfort and health and depend on them to do so. (damn pronouns)

With Ni/Se types it's more about challenge.