Puffing stomach up?

I know that Bearded Dragons puff themselves up to stay afloat in water, but sometimes Cinder puffs his stomach up a little bit randomly, even when there isn't any water around. I have read that beardies do this when they are stressed or irritated, but Cinder is always in his bright, happy colors when it happens. He also flattens out his back when I pet him...I always took ths as a sign of relaxation, but could I be wrong? I have always had these questions buzzing around in my head...today, Cinder was exploring my laptop for the first time and he began to puff himself up a little, like he does when he hears water running. He didn't have any stress marks, he wasn't opening his mouth, or puffing his beard up. His colors were bright! Does anybodies else's beardies do this??
Could somebody please clear this stuff up for me? Thanks...

Could be a couple of different things i guess,

Could be a little bit of a defence thing, as beardies do that to make themselves look bigger then what they are.

or

he could of senced the heat from the laptop and started to flatten out, as thats what they do to bask to heat themselves up more quickly..

But they are both guess's, hopefully this may clear a little bit up, if not, im sure someone with a little more experience will come past and share some light into this.

Cheers,

My Louie freaked me out the other day. She was on her hammock and puffed up super big...had her beard puffed out, mouth wide open....all this to help her shedding! Once a few pieces fell of, she was happy as can be.

IMO, sometimes they do things just to do them. And if they're young, then it's more likely. It could be a new trick they've learned, maybe they're practicing. babies are known to arm wave at crickets before they eat them. obviously it's not submission in that case.

my last beardie used to puff out his beard for just a moment all the time. He wasn't threatened, stressed, or showed any signs of dominance. I came to think of it as his way of stretching. He seemed to do it mostly after his afternoon nap, or an extended basking session.

I agree! I bet mine do it more often then I know about, and I just don't see it.