When wagging your tail hurts so much!

So I come home from work yesterday and as usual get ready to take Mack out for a walk. We keep him contained in the kitchen because we are not quite ready to let him roam the house while we are out all day. We are very fortunate though, he has not left us any "surprises".

He is soooooo excited when I get home that he is wagging his tail and it actually looks like he is putting everything into it, because his butt is wagging just as hard. This is very typical when he is very excited. So I notice that there is some blood streaks on the dishwasher and then on the edge of the wall. Well come to find out he was wagging so hard that he cut his tail. Poor thing! How do you tell a dog to stop wagging his tail when he is sooooo excited?! He has always wagged so hard and always had hit things, but this was the first sign of blood.

So I guess now we have to make sure we get to him right away (which I know was his ploy all along!) and keep him from hitting his tail on anything. I never thought this would be a challenge of owning a dog.....