That's the spirit!

[He doesn't mind that Asriel reaches for his hand, not at all. Mettaton also yearns for physical contact, little that he can benefit from it through actually feeling. He just likes being close to people, ghost or not. He...needs that.

So he would never begrudge Asriel a friend's touch.]

You know I will always be there for you, Asriel. Whatever you need of me, just ask. That is what friends are for, right?