Affection!
'Cos Barney takes turns to lick my forehead - I stroke his nose, then we pause, he cleans my head, then we switch again. And if my hands ever smell tasty - like when I've been handling pellets, etc. then he doesn't lick, he just nips. He'll sometimes lick my mum, but only very briefly - everyone else gets no licks.
Except fro Amber, anyway. :lol: She used to get jealous if Barney licked me and would go off alone and sulk. But recently she's accepted this and will come over to do some licking of her own. But Amber loves licking hair.
I always wonder, with the salt thing... but surely a bunny would lick quite a few people if they wanted salt?