Why is he so stiff when I hugged him?

Today was our last day of soccer season, and my goal was to hug everyone in the team. They all hugged me back except for my guy friend, J. He was stiff and awkward. I hugged him once before, so why do you think he was like that?
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+1 y
He didn't hug me back, he just stood still.
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+1 y
He suddenly grew quiet after my first hug with him.
Why is he so stiff when I hugged him?
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