So my Nikko is 3 months and 2 weeks old. He has a serious issue with nipping and biting I have 2 daughters a 7 and 2 year old. The issue is my 2 yo and and 3 month old dog are the same size and weight basically. He likes to push his weight on her she easily falls over. He will also jump up and once scratched her face. Once she's down he'll nip and bite. I don't really know how to handle this or correct it. Once he plays rough and I try to calm him down by holding him by the collar until he calms down but it never really works. I really need to get this under control before he becomes bigger. I am hoping that this is something that I can handle I would prefer not taking him to training classes cause I'm sure that cost a good amount of money. He's being crate trained and I would like for him to be out of the crate after bathroom breaks but he's overly hyper and always messing and biting on the girls.