Now...I am not an authority on training but, I have Bella who sounds a lot like Dexter. She has always been the excited one out of all three of my girls and the one who will jump up, lick you a gazillion times, wag her tail like it's gonna help her take off in flight...just a wild scene if you can picture that. There has been occasions when she couldn't control her mouth as well and little bits of mouthing (teeth included
) occurred.
Our solution:
Each time she reoffended (
), she was told sternly, "NO!" and then we would turn our backs to her until she calmed down. It took many attempts but, each time she complied, she would get a treat and 99% of the time she is a good lil' girl but, she is just personality-wise...the excitable one in the bunch and possibly will always be a work in progress.
Also remember...you are dealing with a puppy and his antics will linger till he's at least 2 years old but, being diligent and consistent in training on a daily basis is key! Hang in there...it'll get better!