My stealth device is the same as for my nicotine pleasures...a bent stem regular-sized corncob pipe. At home I just stuff some pot into a pipe. For going out with a one-hit backup I just carry an appropriate sized piece of pot in a pill holder and drop it onto some tobacco at the appropriate time. For extended evenings out I'll take 2 identical pipes, one preloaded with pot and the other tobacco. If someone isn't staring at you continuously it's easy to switch in the pot pipe for the tobacco pipe for an occasional hit. If the law approaches, knocking the dottle from one's pipe is not a criminal act, or if necessary the tossing of the whole pipe will cost just a few dollars. I enjoy all the glass, chrome, brass, wood, etc. devices for their cunning, but in my eye they aren't stealthy - they mostly look odd and attention getting. Real stealth is doing it in plain sight and not being comprehended. Nothing homelier than a corncob pipe. Buy a 1 ft x 1 ft section of brass screening from the hardware store from which to cut filters...it will last 20 years. I carry a quarter in my hand on these occasions and when I've lit and hit I cap the pipe with the quarter to snuff the bud.
And the wide variety of scented pipe tobaccos available - Cherry, Captain Black, etc - can be utilized for covering aromas. Bear in mind that the aromatics have been soaked in sugars, liquers, etc. to get that aroma and the downside is that they smoke hot. So smoke them lightly - short and occasional puffs - or they will burn your mouth. But most people like an occasional whiff of an aromatic pipe tobacco and won't hesitate to remark about it...I've been told about how "that smell/pipe reminds me of my grandfather" more times than I can recall. It's nice to get my pleasure in a way that gives a different pleasure to others.
I've been using this method since I was 20. More than 40 years ago. Always works.