Why is he mocking me?

So guys my ex and I are on good terms were friends. We recently hung out and we was just chatting and laughing and he started mocking my laugh. I replied stop mocking meee and laughed more and he started chuckling. This isn't the first time he mocked my laugh. We was once on call before and he mocked my laugh and us usual I would tell him noo stop and laugh more and he would chuckle. I'm getting the vibes that we are bonding I'm not thinking relationship wise I genuinely feel we are bonding with each other and growing a good connection as friends. I never been mocked before so yes I have to ask what's with this behavior or is he bullying me? I'm sure it not bullying but again I just have to ask.
Why is he mocking me?
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