I could really use a hug.
I'll give you a hug if you want one.
Thank you, I'm going to go in for a hug now.
Physical contact is part of the human experience. It is perfectly okay to ask for a hug if you are feeling down or upset as long as the other person is comfortable giving one.
Yeah I know, I just wanted to ask so I knew if you were okay with it.
That's a good thing. It's fine to want a hug and really respectable of you to ask me before just going for one.