because he understands reactions that are supposed to follow actions. or feelings.
so if you gave him pudding, and then told him to say "grazie", he'd figure out pretty quickly that when he's handed pudding the response is to say "grazie". that doesn't mean he'd make the leap to "that's what you always do when someone does something nice for you", but he'd get it in that specific instance pretty fast.
one of his friends loves him a lot and gets excited about him, and kisses his face like that when he sees him. so he made the connection that when he feels excited like that, the way to show it is by kissing someone like that.
no subject
so if you gave him pudding, and then told him to say "grazie", he'd figure out pretty quickly that when he's handed pudding the response is to say "grazie". that doesn't mean he'd make the leap to "that's what you always do when someone does something nice for you", but he'd get it in that specific instance pretty fast.
one of his friends loves him a lot and gets excited about him, and kisses his face like that when he sees him. so he made the connection that when he feels excited like that, the way to show it is by kissing someone like that.