I'm a corrections officer. I would say at least 75% of my inmates are bigger/stronger than me. I defused a situation like this just a week ago where a guy who is quite literally 350lbs of pure muscle on a 6'3 frame was in the face of someone who was all of 5'10 and 180lbs if that.

I didn't know why they were face to face, but I broke that up in about 10 seconds without any violence. I immediately got between them (not supposed to do that, but whatever, it works for me) turned to the bigger guy and said "Mike, whatever the fuck you think is about to happen...? It's not. Go to your cell. NOW." "But-" "NOW!!! This is not a negotiation, go now, we'll talk in a minute when you're calm. Go." And away he went. He could have eaten me alive, he could have just reached around me and throttled this kid without laying a hand on me, but I foster as amicable a relationship with the inmates as I can and I have never had a fight in a block I was managing (in 3 years of this job).

The thing is, Mike has severe anger issues, and what I didn't know is that the mouthy little twerp he was eye to eye with had slapped him while my back was turned, and that's what caused the situation. If you asked any CO what happens if a smaller inmate slaps a larger inmate in front of a group of people, they'll tell you that smaller person is likely going to be in the hospital.

You don't need size. It's not about flexing your muscles at them, it's about them caring enough about what you want to actually listen when you tell them something. However you get to that situation, however long it takes, it is infinitely better than simply trying to out-flex them.