Nagelfar
Bluelight Crew
Sure, it's not something you can do at a party with all your friends (though I don't doubt those parties exist!)
Besides whether the parties themselves exist, to do it in a social & unfriendly to such things environment: a nice 3ml veterinary syringe (with no needle of course) can be inserted in less than a minute in a bathroom from a coat pocket in my case, and left there, with trousers redonned and no awkward gait, reach back there as if to scratch and push the plunger down, go to the restroom later to take out (making sure to have a baggie, back in pocket, and properly disposed of at another time). Though I'm sure many would need to practice at home first ;-)