This is another quite enjoyable faze, in fact you may not even notice when it starts, but believe me you will notice when it ends. This is the time when they'll strut what you taught them they won't be much different from the first stage, you may even be able to start teaching them new impressive tricks, but don't forget to always brush up on the basics and enjoy this time. The only 'down' side to this stage is around this time, they'll be loosing their puppy teeth, yes teeth will come out, usually they'll swallow them but sometimes they spit them out and you can save them. It usually happens between 4 and 5 months, don't worry the all you have to do is help ease the pain and discomfort of toothloss. Provide plenty of chew toys and sit down and help your puppy get to know to chew the toys (or they'll chew everything else!) Their gums will be bleeding also, don't get scared, they'll be fine, you can also put some low sodium chicken soup or orange juice in an ice cube tray and give them an easy melt ice cube treat, try to keep foods soft, canned, or soak kibble to ease the pain of chewing.