What does it mean when my colleague squeezes my waist?

I have a colleague who /always/ squeezes my waist. He's the type of guy who's friends with everyone. So he's very playful. LOVES to tease/make fun of people (in a lighthearted way) he's basically the clown in our office. Although he does squeeze other girls in the office, he usually just squeezes them on the arm. Me however, he would always squeeze my waist. Especially when no one's looking/no one's around. Most of the time I just don't react or if he squeezes too tight, i would retaliate by punching him on the arm.

Maybe because I'm younger and he looks at me like a sister? I don't know. He's married by the way.
What does it mean when my colleague squeezes my waist?
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