It is still sex. It is SEXUAL stimulation from whatever source and is it intentional and done for sexual pleasure.
That is what it is.
It is immoral. I bet you don’t STIMULATE your children that way, right? Because you know its immoral.
I wouldn’t stimulate children that way because I’m not attracted to children. And no, sexual is not enough to make it immoral. Just like drinking alchohol is not immoral, while drunkeness is immoral.