I don't have experience of the condition - just to wish you all the best with Tubby.

We have to catch Jessica every few months and brush her, down near her tail. It's very like Phred's description - a two person job and a towel over her head - and we get enough dead hair out to make an extra cat. I think she can't clean it properly because maybe she's not quite as flexible as she used to be and perhaps a little round? There has never been any kind of secretion or sticky substance associated with this though.

The description of stud tail sounds very similar. Perhaps you could phone the vet's initially to describe it and see what they think.