The boys have never done this before. Granted, they play and fight with each other though generally calm down after a few minutes. There's only been one occasion that any of them have injured each other and it was quickly dealt with. However, I'm sitting here tonight and my two oldest boys, Nexus and Bane are going at it. They're squealing and wrestling and, though there's no blood, it making me nervous. All of them seem to be extremely energized at the moment. Even went to extend my hand with some cheerios and, in the moment, get bitten lightly by one of them in excitement. Is this normal? Should I be concerned? If so, what should I be doing to address the issue?