I would let it out occasionally, never yell but get very defensive and sometimes attacking/accusing. It caused problems. Finally I told her sometimes I need to be mad and angry and work through those feelings...I need to be allowed to experience them in a safe and accepting environment. I asked how I could go about this without causing problems and she said when I first come in, tell her I'm feeling angry or need to be angry today, and that we will figure out a way together for me to express that anger.

I haven't done this much yet for the same reason you mentioned. It's not the same having to explain or announce it beforehand and not as therapeutic as being angry in the moment.