my boys tail looks a bit like that a few days before he sheds, although he's missing a third of his tail, so just the end bit goes a bit darker like in your picture, once he's shed it goes back to normal :)
Ed did a similar thing today when I fed him crickets. A half chewed up cricket came up, then before I had a chance to get rid of it he chewed it up and swallowed it again. Think he'd just been gobbling them down too quickly - he has been a very greedy little boy today after a couple of weeks of...
Eddie is my first beardie too .... I've been worrying about him for a couple of weeks now, he's been sleeping most of the day and eating hardly any thing that I give him, this has reassured me slightly as I was worrying that I was doing something wrong. he's been up and about a fair bit this...