Hi there Shamer.

We are battling with the exactly same problem! How to express anger without feeling completely unsafe and wrong?
It's a tough thing to do...I can actually express my anger to a certain degree with a very close friend of mine. I trust that s/he doesn't judge me for being angry but actually encourages me to be angry!

I usually stomp my feet to ground, knock objects against table and talk about why I'm so angry.
Very often parts inside abuse others for being angry or they simply prevent them from being angry because we have learned that being angry is bad. And that being angry makes us the same as our original abusers.

And that is not true! Being angry is good and it's super important feeling.

It helps you to stand up for yourself and to note you when you are being hurt or treated badly.
My body also hurts all over when I'm mad.

But I just can't seem to release all that energy! Of course it would be important not to release all of it at once! It would end up badly.

So if you could (and me aswell!) learn to release a teeny tiny bit of anger at a time...maybe 0,1% of the whole package of anger?

As long as it's comfortable and safe enough to let out a tiny bit of anger out, it could eventually work out! ^_^
The feeling of being safe also comes from the inside. When parts are angry at each other, they can induce flashbacks and act abusively simply to stop you from telling about your pain and feeling anger. You shouldn't be blamed for making the body hurt! It's hard already to cope with anger and other parts are not helping anymore by accusing you of being at fault.

Would it help your situation if you could talk with these parts to stop your blaming?