Swizzling
Swizzling often seems to confound people. I think the culprits of confusion are the swizzle straw and swizzle stick. If you look at either one of these, they don't seem to offer much utility other than to hold a garnish or to blow pathetic bubbles into your drink. Until you see a traditional swizzle stick (“le bois lélé”), a real stick and not your garnish holder, swizzling just seems like a mellow form of stirring. But that's entirely wrong. It is more of a hand-powered, old-school stick blender, but it is a real stick.
Traditionally, swizzling was used to mix up switchels, a fermented vinegar with honey or molasses added to it. In order to combine the thick sweetener, you had to stir really hard. Nowadays, we just use a honey or molasses syrup instead. Back in olden times, you would have used a real swizzle stick, which was a branch from the....swizzlestick tree! Quararibea turbinate, a small shrub-like tree native to the lesser Antilles. A traditional wooden swizzle stick from the swizzlestick tree is called a bois lélé. You'd use one of these short fingered fans on a long shaft to rapid mix up a drink. Allegedly, these would produce a frothy head, but I can't recall a swizzled recipe that includes ingredients that would truly froth.
Why swizzle
This method quickly chills, dilutes, and aerates a drink with minimal equipment. It also chills the serving vessel.
What you’ll need
There are traditional 
What type of ice? Go smaller, which will help to speed things along. Cracked, crushed, our pebble ice. Cubes will be harder for you to move the swizzle stick through, and also dilute and chill less quickly.
For crushing ice, I highly recommend a good 
How to swizzle
To swizzle a drink, you start by putting the ingredients in your serving vessel, add some ice, then put in the bois lele. Then quickly rotate the bois lélé shaft between your palms, as if using a firestarter bow, or an immersion blender that wasn't chopping up the ice - just spin it, and spin it fast, while moving it up and down in the vessel. Then add more ice and repeat.
How long to swizzle? There isn't a clear consensus on a specific length of time, other than to swizzle until the outside is frosty. I recommend a 8-10 second swizzle. As mentioned, swizzling is similar to shaking, in that it is chaotic and fast. Unlike shaking, swizzling is typically performed with crushed and pebbled ice, which will dissolve more rapidly than the cubes that are used for shaking. Therefore, keep your swizzling time less than shaking.
Essentially, you're performing a rapid, violent stir, with more aeration than can be achieved by a typical stirring method. If you don't have a bois lélé, you can produce similar results with a barspoon.
Swizzled drinks are not typically strained, so swizzle in the vessel you intend to serve the drink in. A taller glass is recommended, such as a Collins, Zombie, or a pint glass. As you swizzle, the rapid cooling should cause frost to form on the outside of the glass. Often, swizzled drinks are served with a napkin around the glass, which helps to keep the frost, when it melts, from creating a puddle on your bar. It also helps to insulate your serving vessel a little bit, and maybe keeps the drinker's fingers from getting frostbite. But if I'm drinking a swizzle, it's probably dang ol' hot outside and I want that coldness on my hands.