@ipodjulator
You can get 5 grammes of menthol crystals at the pharmacy for a buck or something, it's dirt cheap.
Take a 5ml amber glass dropper bottle (also from the pharmacy) and put in 1ml (ie about a fifth of the bottle) of alcohol, either PGA or just rum, vodka or whatever.
Sprinkle in a small amount of menthol crystals, about what you can get on the tip of the handle end of a teaspoon for example. 5 grammes of menthol will last you for ever...
Shake well. It will be fully dissolved in about 5 minutes especially if the alcohol is slightly warmed.
With the dopper, put ONE DROP ONLY of menthol 'juice' in whatever you're making up. Too much and you get a diabolical medical taste, it's vile. Just enough and it's real nice. It only takes a tiny amount. Menthol is about the strongest thing going (well, apart from ethyl mercaptan or TNT, I guess.)