Yes it takes a while for a proper concentration to build up in the body, it isn't nearly as potent as the more modern inhalational anaesthetics such as fr.ex sevofluorane, best way in my experience to use it via inhalation is a plastic bottle with a little bit of some sort of absorbent material to act like a wick in the bottom, and filling the bottle to slightly below the level reached by the absorbent, doesn't matter what, fabric, bog roll, anything like that works. Although I'd suggest if bog roll be used, that it should be unused bog roll, and not some thats been used for wiping somebody's chocolate starfish beforehand
Orally it lasts considerably longer, it hits harder too, quite a bit more potent. Best way to use it is to do both IMO, that is to say, an oral dose followed up with inhalation. No need to fart about with unscrewing and screwing the cap back on, if you wish to let the vapor concentration build up, just stick the ball of your thumb over the bottle neck and give it a bit of a shake, then slowly keep breathing in through the nose (pressed to the bottle neck) and out through the mouth.
Oral dosage is about a 5-10ml to start with. Easiest way to consume it is poured onto a shot of spirit (alcoholic) and downed in one, followed up by a chaser of whatever suits your taste, beer, cola, doesn't matter much, its just to wash it down.
Or, a cocktail I came up with, that I call a 'manhattan project'
You need:
Vodka (GOOD vodka mind you, none of that cheapass rough as shit toilet cleaner/paint stripper grade hobo-fuel garbage.
Lime soda, preferably tesco own brand cheap lime fizzy pop.
Codeine linctus, 'bells' or 'care+' are the brands to use if available in your country, these are UK brands, and are flavoured/preserved with chloroform, this is vital IMO for the right taste of the drink.
And of course, diethyl or diisopropyl ether, diethyl tastes better IMO.
Layer the codeine syrup on the bottom and then CAREFULLY poure over a mixture of vodka and lime soda, a squeeze of fresh lime doesn't go amiss either. And get a little plastic measuring cup, like the kind used for dispensing liquid medicines, make sure first that the ether won't melt it, but something that will float on top, fill with ether, and get a couple of lime wedges, stick them on the side of the glass close together to hold the cup of ether between them, add a third if needs be to bridge the first two slices of lime, and prevent the ether spilling or the little shooter glass floating away when you try and drink it, basically the idea is to lock it in place with lime slices.
Then think 'jagerbomb', ether goes down first then gets washed down by the vodka and lime mixture, and finally there is the sweet, thick, sugary codeine syrup with its aromatic chloroform-ey taste and scent to cleanse the palate at the bottom. Lovely. And its got a kick like a cruise missile too. Hence my christening it the manhattan project (after the manhattan cocktail, plus a tongue in cheek reference to the US nuclear program.
And if you want to smoke anything, do it BEFORE making and drinking this lil' sucker. And don't use shitty starting fluid either, certainly don't drink it, use the best quality diethyl or diisopropyl ether you can get. No need for spectroscopy grade or anything, but do use good quality ether, that of course goes triply so if your going to drink it.
Drinking lasts longer and needs considerably less than inhalation alone. Also it doesn't give a hangover like ethanol does, at least it never has me, although you can smell/taste it on your breath for a fair while after.
And in case the message about not using starting fluid didn't get through, there is always a small proportion of high-boiling cylinder lubricant in it, plus an aliphatic alkane solvent, usually heptane. But I've seen a list of all sorts, diethyl/diisopropyl ether mixture with acetone, heptane, xylene and denatured alcohol, depending on the brand. It can be distilled with care for a usable solvent but is in no way ever fit for consumption. It does make for a handy spray on lubricant for ground glass joints when fitting lab glass together though, since the ether and alkane quickly evaporate off leaving a thin film of the cylinder oil, requiring much less greasy crap than using say, vaseline or other lubricants.