While the OP’s gif arguably shows the whole booblate moving up and down instead of just the breasts jiggling (so it’s not improbable… given the armor is really badly fitted and worn with zero chest support), it gets worse…

…much worse…

Yeah, don’t kid yourselves, rebloggers: that character’s boobs do actually bend metal around them. It’s just not all that obvious in the top gif.

No wonder so many people react to such design and animation by quoting Miyazaki on that real thing which he totally said.

~Ozzie