After i brush my teeth i have a white slim in my mouth, what is it?

Gum tissue sloughing: You are probably slightly allergic to the toothpaste i.e. Some ingredient in the toothpaste, you are using and it is irritating your gum tissue. Many people get this, it is fairly common. Especially cinnamon or spearmint flavored toothpaste seem to do that to some peoples gums. Just try a different toothpaste to get rid of that effect.