My ferret just randomly started licking my face, he's never done that before, why?

I had heard that ferrets give kisses but mine never have before. I got my second ferret, Badger about a month ago. He's almost 6 months old now. I play with him all the time but he's never done that. He just woke up a little while ago and i was holding him and scratching the back of his neck and he just randomly starts licking my face like CRAZY! I'm not complaining but I just want to know why he all of sudden started doing that when he had never done that before. My older ferret never does that. EVER.