Why doesn't he ask for nudes anymore?

My friend (old fwb) used to ask for nudes all the time when we were physical with each other. We decided to go back to being just friends but recently he's been really flirty and affectionate with me and has hinted that he's definitely still interested.
Usually he'll make a joke and ask for them but this time he doesn't ask or make as many sexual jokes anymore.
Why doesn't he ask for nudes anymore?
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