A small fog machine, as usually found at pop music venues, worn under a skirt, dress or kilt.
(R&D's still working on the most appropriate attachment mechanism).
Also available for puttys and tophats.-- FlyingToaster, Mar 22 2015 Hat_20of_20Mist as PRE-available for hats!! [xenzag, Mar 23 2015] You wouldn't want to distort the hang of the skirt, so you're probably attaching this thing to a leg. I'm seeing some chafing - or a very peculiar-looking sporran.-- pertinax, Mar 22 2015 Admittedly, the design was originally conceived for kilts (there being no leg-crossing involved, also with a custom-made kilt, the sporran provides the least amount of botherage) and hoop skirts.
Indeed, Marketing had the "Oh what does a Scottie wear under his kilt ?" ads made up less than 30 seconds after the idea was broached in the pub by one of the interns (though, on recollection, it could have come from under the table in the general vicinity of the interns).
Engineering however has risen to the occasion, prototyping some rather slimline devices that are no more intrusive in normal operation than a concealed holster, for formal and even above-the-knee dresses and skirts.
Miniskirts are proving to be quite a challenge, but they continue to promise "any day now", every time more test subjects are requested.-- FlyingToaster, Mar 22 2015 Why can't I use it in my pants? I want jets of fog to shoot out my legs when I laugh. Also my fly, because I left it open, which is why I am laughing.-- bungston, Mar 22 2015 The aforementioned "puttys" can do that for pants, meanwhile we've jury-rigged a pair up with those things you use to keep socks from sagging, though they are less than useful while jogging.-- FlyingToaster, Mar 22 2015 Could rig something up fairly compact using dry ice.-- tatterdemalion, Mar 22 2015 /something up fairly compact /
Tats, are you referring to the in-pants version? Because with dry ice I am sure that would be true.-- bungston, Mar 23 2015 With regard to pants I try to be flexible.-- tatterdemalion, Mar 23 2015 [tatterdemalion], that would be stretch pants, I think. I like this idea. Especially walking home on a foggy San Francisco night, down the steep hills, with lamp posts all around. Very surreal.-- blissmiss, Mar 23 2015 Single use dry ice version is relatively simply, and doesn't require a lot more than a hot water bottle (and some insulation) strapped to the inner thigh.
Any sort of multi-use system including the most likely oil or glycerol types are going to be a little more difficult to pull off, since you need a pump of some sort.
(I may have thought about this for costuming purposes previously).-- MechE, Mar 23 2015 Which one's the one which smells vaguely perfumey ?-- FlyingToaster, Mar 23 2015 That would probably be glycol or glycerine (slightly sweet or "burned sugar") smell. Most people avoid the mineral oil these days because some people have an iffy reaction to them, but they tend to have a slightly dark or musky smell.
Dry ice has no particular smell, which makes it a favorite (although I wouldn't recommend lying down in it, lots and lots of CO2 in the mix).-- MechE, Mar 23 2015 Awesome-- Voice, Mar 23 2015 GROG like [+]-- Grogster, Mar 23 2015 Just have some kind of chemical that turns red in the air, when coming in contact with methanethiol or dimethyl sulfide, like they (urban legend: don't) use in the pool for detecting uric acid and other chemical compounds. Then this wouldn't be gender or clothing specific.-- pashute, Mar 25 2015 ^ what ?-- FlyingToaster, Mar 26 2015 random, halfbakery