Looks like they were playing "Follow the Leader" and looks like they are going to be best friends soon.

As for the purring/licking/biting thing, Pouncer does it too. He does it when I'm lying in bed, he comes up and sits on my chest and gets scratchies. Purrs a million miles a minute and then starts licking my finger tips. Then soft, sweet little nibbles, then CHOMP. Then me going, "OUCH." Then I go back to petting him and the whole cycle begins again.

What a pretty tail - glad you got a shot that shows it!