Id offer a different spin.
Punish him.
>>If Easievibe just lets it bounce off him like a tennis ball off a tank (control over his own mental state), and instead displays warmth (high dominance character) then Bitch-Dude feels stupid and doesn't do it as much. Eventually, Bitch-Dude will stop. In the short term, making Bitch-Dude feel stupid may result in him getting more aggressive, just keep it up and you'll win in the end.
By doing that you are showing it is acceptable behavior.
If you are taking cookies for a cookie jar and it rewards you with warmth, would you stop?
Instead, "reward" him with cold.
I assume that you are a naturally warm guy. Good to be around and like able.
I suggest that next time he calls you bitch, calming and warmly tell him that you dont like that, and if he would please, dont do it again.
If he does again, this is where your behaviour changes.
Normally your ego would spike and you'd get all irritated.
Instead, go completely cold. Deadpan. Neutral. Like a complete 180 from your normal warm self to completly cold. Not angry. Just a total devoid lack of emotions.
Your housemate will pick this up and say, "whats wrong?"
Calmly say that "Dont worry, I'm not angry..."
If he presses you just say "I dont like ANYONE saying things to put me down not even in jest ESCPECIALLY not a friend."
Whenever he calls you bitch again, just go cold.
An effective but quite cold method
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The theory behind this is that normally you are a source of good emotions. Now because he fucked up, you cut him off from that source. His fault entirely. But when he starts behaving, you go back to your normal warm character!
This works on girls too!