Sacred Haven of Debauchery

stuffing some kind of vapor generator into your mouth

Although there's nothing inherently good about it, people often try to use "electronic cigarettes" to quit regular cigarettes. In my opinion, that's a worthwhile endeavor. At the very least, the vapor is less irritating to those around you than smoke and the unpleasant cigarette smell from your mouth.

or, even more so, fiddling with some three-pronged thing in your hands

"Even more so"? Haha. Well, many people, in one way or another, try to occupy their motor functions when they're thinking or doing something. Back in my school days, guys were massively spinning pens; it was a trendy thing... They even competed in skill, seeing who could do the most complex trick with a pen. And why not? There are genuinely irritating motor habits, like biting your nails, and the spinner option seems quite harmless.