We have had the same problems with our 4 month old gs. She really likes to play bite and our trainer said that it's normal for puppies because that's how they play with their litter mates. If it continues and she wants to use you as a chew toy like ours does then you can put her into a submissive position by holding the scruff of her neck and pushing her to the floor, not hard tho! Hold her that way until her body relaxes and then you can give the release command. When you put her into that position you can say "no bite" and once she stops and relaxes praise praise praise her! You always want her to know when she's done a good job at what you asked her to do. I hope this helps!! Be patient and good luck!