Cotton candy - it's not just for eating anymore

I still cannot get over the fact that I have to coax and bribe a dog in order to rub and scratch his back because I assure you that no one, probably not even a serial killer, would have to coax or bribe me to let him/her rub or scratch my back.  With that said, Alvin is making progress in that department.  He has started to allow me to pet him when I am standing up over him.  What has been so very helpful is that Alvin watches everything the other dogs do and he is definitely braver with them around.  When the two other dogs greet me, Alvin has started to get in on the welcome party and I can briefly pet him on his back and neck.  The top of the head is still way off limits but I can't fault him on that because if given the choice, who wants the top of their head scratched when they can get their back scratched?  Alvin probably has a whole master plan of how he is training me and yet, I'm the idiot writing the blog.
I have noticed that I have not seen Alvin groom himself at all since he came here.  He got a bit of very bright blue cotton candy on his leg (never mind how it got there) and I ended up leaving it because it was something I could see if he licked off and I knew he had no objection to eating cotton candy (again, never mind how I knew that).  I don't know if his lack of grooming is another issue with his mouth, or his developmental delays, or he is just still in survival mode and hasn't relaxed enough?  The blue cotton candy remained on his leg for several days until I wiped it off.  All of his mouth issues are still there, although he is not doing the pushing motion on me nearly as much as he used to.  He is continuing to hold his tongue out and he licks things so oddly.  I don't know exactly how he does it but it's like he doesn't have good control over his tongue and so sometimes he licks things on the way up, or sideways, or with the bottom of his tongue, although he does manage to get whatever he is licking.  I have been giving him food in small, clear containers and holding them while he licks the food out so that I can get a better look at what his tongue is doing.  Initially it just looks like oral mayhem with his tongue going every which way but then he seems to get into a rhythm of sorts and it looks normal.  It's so odd.  I have to be careful about giving him anything directly by hand because it's usually either confusing to him because he can't seem to figure out how to take the food or he nearly takes off one of my fingers because he bites into it.  This system is counter-productive to lowering his anxiety because when trying to hand him something I then anticipate him clamping down on my finger, do a little jump, drop the food, and the best Alvin can do is catch it on the down side of his circles that I induce.  I anticipate that Alvin may soon pack his bones and get the heck out of here!