Dominace issues with Brutus

For the last two days I am seeing a major change in Brutus. He has rushed at Maggie with a vengence, got very dominant with Keith while they were playing, started slinging his head and getting very rough. He wouldn't mind, Keith finally held him down to get him in control. Not harsh, just held him. Tonight I was spending some quality time with Roxie. He comes running out of the bedroom and starts slinging that head and humping her. He would not mind again. I finally got him off her, and got him to sit, she escaped to the bedroom and he is now laying down by me, asleep. I know he is in adolescence, but this is not his normal self. Any ideas what is going on? Also, how do I stop this quickly?

I am sure I am not of much help but I know Teddy went through a period of adolescence. he would not mind for nothing. We only had Teddy at the time (well we still only have TEddy) but he would take after other dogs and try to bite their ears and hump them and everything else. We just tried to do a little more training with him and used the NILIF like no one's business. He actually didn't really improve too much until he got a little bit older. NOW he is past adolescence and he is VERY friendly with other dogs and is getting LESS excitable around people. I could be wrong and I don't want to set myself up for flaming for giving incorrect advice *blush* so take this at face value but eventually he DID grow out of it. Since you have other dogs living in your home it might be a little different. I have to admit I noticed a big change when he was around my moms dog (shih tzu/pug mix) and she is very bossy and put him in his place MANY times. he seemed to realize that he could not just do whatever he wanted when ever he wanted with no repercussions

Well Roxie just put him back in his place this morning. He stood over her with his tail swinging high(mischief mode) and the head slinging thing. She had enough. He backed down. What is this head slinging thing? I don't think I have ever had a dog that has done that. I have always practiced the nilif, he does not get treats until sitting, and all the dogs know to wait before eating. I am having to repeat everything thing to him two or three times. It seems his brain has some, "duh, are you talking to me" syndrome.
Maggie and Brutus get along fine outside, it is in the house where he must chase and annoy her. I swear he was looking at her as if she was a rabbit yesterday. I don't like that look.
McKinley came over yesterday and he was normal around her. Apparently half of his brain is still working, it's the other half that worries me. Where is it?