It is a tough emotion to shut down. Getting out of it depends on the cause as well. Is your rage a reaction to something or 'just' BP rage? Exercise helps me, even just a fast walk. Uplifting music also helps but sometimes positivity pisses me off even more and I oddly find angry music cathartic. Tearing up newspaper, or any kind of paper helps me at times. Then there is good ole distraction, anything that occupies your mind and takes you away from the dark thoughts and feelings.

Then of course, if all else fails, there are meds. I take Clonazepam and if agitated and getting out of control Olanzapine (Zyprexa). If really bad I need high doses to totally 'check out' and then hopefully sleep it off.

hope you feel calmer soon.