First and foremost, do a better job of keeping your secrets secret from him. If he has anger issues like you describe, best to stay as far away from this person you live with as often as you can.
blow one of his to your mother, and let him know if he doesn't stop you'll tell all his friends. whether you do or don't it will leave him worried that you already did and wonder who you told and if they do really know. It will make him paranoid and uncomfortable and he will probably not do it to you anymore. and guard your own better.
just don't tell him anything, spill some of his secrets too
Duct tape his mouth shut
Tell him you will make him a cupcake! Haha nah.
Litteraly just drag him into a room and talk to him. Calm him down and talk about stuff he likes. Little kids feed into that.