7 year old male aggression

Question
My 7 year old male has started being aggressive towards me when I TRY to
get him to go outside.  The habit has become, first thing in the mornings, or
after he has already gone out and he comes back in and sits somewhere he is
not allowed to sit and i tell him to get up and he snarls and snaps at me
showing his ugliest face and all his teeth.  Now this is a face I only see when
my females are in heat and I won't let him near them or when he decides I
can't get near the females.  Never to the point that he didnt back down from
my standing and holding my own and telling him to heal.  This morning he
tried to take my head off.  I do not push my luck, I have had him since he was
6 weeks old, and he always gives me the go ahead.  But today he put me in
my place and I had to get a broom and push his hiney off the bed meanwhile
he was being nasty towards me. Why all the sudden the change in attitude
when he gets in a place he doesnt want to get up from?

Answer
Wow, I don't know what caused the change but he has taken over as 'pack leader'. First thing, no more sleeping on your bed,he sleeps in a crate in another room from now on. Second thing, immediately find a trainer to come and help you with these aggression issues because dog aggression is not something to take lightly or ignore and wait for it to go away because it will get worse. Go to the APDT,CCPDT,Animal Behavior Training & Associates and Animal Behavior College websites and use their trainer search engines to find a trainer near you that knows how to deal with aggression and can help you work through these issues and regain your pack leader position.