Guy's Behavior

A guy jokingly said "I'd kiss your feet" and after responding by saying yes he actually did it, would you consider it flirty or pure cringe?

We were alone just talking about silly things. He said later if we weren't alone he'd never do that.
And of course it'll always stay between us.

It just happened, during our talk I told him something secret about my relative and he said "I'd kiss your feet if that really happened"
I thought what he meant was he wants a proof because it was unbelievable so I didn't really took him for word.
After I showed him the picture of that thing which I told him he just said, "Oh god, I'll have to do it now" and really went down kissed my feet.
I just laughed it off because we didn't have any flirty talk nor we ever had any sexual tension. And for rest of the time we were normally talking like it's nothing.

But now I'm can't stop thinking about it.
Do you think it was flirty? And should I bring it up next time we meet?
A guy jokingly said "I'd kiss your feet" and after responding by saying yes he actually did it, would you consider it flirty or pure cringe?
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