I always flex my left one and I think that has made it bigger than the right one. Now I am also left handed(no sure if that makes a difference or not). But my left is noticably bigger than my right.
Having your arms in perfect proportion is nearly impossible. Even the pros struggle with it. If you're left handed, it's likely your left arm will be bigger. It just depends on how much it bothers you.
Flexing - If you mean squeezing at the top of a contraction, db curl for example, yes. It's a good thing to get in the habit of doing, for all your excercises.
If you mean posing in front of your gym's mirror, you're on your own there.
Technically yes. Just bending your arm stimulates the muscle. Doesn't compare to resistence training though. I don't see the point in doing it, unless you want everyone in the gym to laugh and point.
Nah...I use my left hand for self amusement. I'm fairly ambidextrous.
I think tennis is the responsible party.
Anyways 20% is more accurate. I was having fun...thought it was obvious.
Mine are exactly the same size with the measuring tape, but very different shape....
My left peak is higher, but my right doesn't seem to stick up as much.... I'm always amazed when they measure the same girth. I could swear my left is bigger.