Guy adjusting his pants?

If a teenage boy keeps kind of pulling/tugging at the center of the waist on his basketball shorts, what does that mean? No hands in pants, no actually grabbing anything, but his hand keeps kind of automatically heading there/hovering over his crotch as he talks to me and then sometimes he'll kind of tug on the waistband. I've seen him do this several times when I've had conversations with him.

His pants looked kind of tight-ish but I really couldn't tell/didn't want to *look*.
Guy adjusting his pants?
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