I pull Tino's back in a rubber/silicone band bc if I don't his will either knot up like Sully's or will get in his mouth! Does Sully rub his paws on the top of his head to rub his ears? It looks like that may be what's causing the mat. Tino is just a little older than Sully (13 months). Hey if you come to the meet up in Asheville, maybe Tino can give him some hair tips!