Guys, when you touch a girl on the waist, what does it mean?

As in, would this be something you would do to a girl you have a crush on? My crush did that last time while we were saying good bye, I touched him on the shoulder slightly and he returned the touch by placing his hand on my waist for a bit. There have been other touched from his side such as touches on the shoulder, arm, e.t.c.

I know I'm looking hard into this but I really like him and would like to know what it could mean!