How do strong men do that muscle breast twich?

I’m female, and I can do it.
There is no trick. You only need to be familiar enough with your body to flex certain muscles. It is no different than showing off a bicep, or raising your eyebrows.
Here is s simple way to become familiar with how it feels to flex your pecs. Pecs is short for pectorals.
Try squeezing one arm close to your body, then flex your bicep. Your pecs on that side should flex also. When it does, remember the sensation. After doing it that way a few times you should be able to get better at it.

Muscle breast twitch may be one of your best, RedDeer, cracks me up.
You should watch youtube and see the old west ladies do it and spin tassles, its pretty great. :D

And like Patty said, its just muscle flexing.

Whats really fun is watching a group of gym rat guys all seeing who does it best, like a bunch of hs boys, hilarious.

Thing is, doing it isn’t hard, just you run the risk of looking a right tit.

It’s just like flexing any other muscle. If you can’t do it. Yeah. I guess you need to exercise your pectorals more…

Don’t think you need to be strong. My dad was a 5’6” wimp and he could do it. Practice, practice, practice