Waist training is the the practice of wearing a corset to achieve a smaller waist measurement, corseted or uncorseted. Tightlacing, depending on whom you ask, is either a 23/7 corseted lifestyle, or simply lacing one's corset to a particularly snug and dramatic waist reduction. Neither can be accomplished without a well-made, well-fitted corset.
What is it?
The terms "waist training" and "tightlacing" refer to certain practices of corsetwearing, but their definitions are flexible, overlapping and sometimes interchangeable, and mean different things to different people. People often try to quantify them with a number of inches and/or duration of wear.
Generally speaking, waist training is the practice of wearing a corset to achieve a smaller waist measurement, corseted or uncorseted.
Tightlacing, to some, means wearing a corset literally 23/7 (removing it only to bathe), whereas the definition I lean towards is wearing a corset with a dramatic waist reduction. There is no specific number of inches that equates to a dramatic reduction due to the variance of size as compressibility of corset wearers: 5" off a 24" waist is sizable, 6" off a 36" waist is minimal, and so forth.
How does it work?
There are no "rules" for waist training except to be extremely mindful of your body to prevent damage and maximize results. It is more important to wear your corset often than to wear it exceptionally tight or for very long periods of time. This is the same theory that would apply if learning a musical instrument or any other skill. The muscle memory is better reinforced by frequent repetitions than by being pushed beyond comfort.
To see results, you should wear your corset at least a few times a week for several hours. Lace your self in, but before tying off, take a deep breath through your lower ribs (but not your stomach). You may find the gap opening naturally a bit at the waist, or feel as if it needs to. If you're intending to wear your corset all day (8+ hours), lace half an inch or an inch looser than you think you need to. You can always go tighter next time, but if you lace too tight you're just going to want to take it off. Remember that your corset will need to "break in" when you first get it; over time it will mold to your body and become more comfortable. (A corset will always break in after repeated wearings, even if they are spaced far apart, but your body will only mold to the corset with frequent wearings.)
Do I need a custom corset?
It is often said that if one is to train or tightlace, a fully custom corset is an absolute necessity. I would politely disagree with this statement for a variety of reasons, though I would certainly not go so far as to say this is never the case. As one begins training, the natural figure is probably still within the realm of ready-to-wear sizing. Even if you have a non-standard figure (short waisted, large busted, scoliosis, etc), this can often be corrected with lesser alterations to ready to wear corset patterns. If the corset fits on your body, both aesthetically and in terms of comfort, there is no reason why a ready to wear or altered ready to wear is not a serviceable option. A custom corset is a sizeable investment and the intended corsetmaker and frequency of wearings should be carefully considered before purchase.
For both ready to wear and custom corsets, it's important to find a corsetmaker whose shape, from proportion to hip spring to posture, suits your body. A mass-produced corset from an off-site factory will not have the same quality of shape and structure as a hand-made corset, crafted on the corsetiere's premises, and will also have fewer options for alterations and customization. Even when going handmade, not all corsetmakers are created equal. Along with the obvious aesthetic differences, we each have subtle or not-so-subtle differences in our patterning techniques and favored body types.
Pop Antique corsets are particularly well-suited to waist trainers and tightlacers because of the signature cupped rib shape. This allows for waist reductions that are simultaneously more dramatic and comfortable, particularly for those with non-compressible ribs. Even the same amount of waist reduction will look more dramatic with this shape, because it is concentrated into a smaller area.
Is it dangerous?
While the negative propaganda about corsets is often untrue, undeserved, and without basis in fact, it is still possible to cause discomfort or strain with a corset. Various health conditions may leave one more at risk to this.
The more you wear your corset, the less stress on the muscles and bones of your back. Many find this a blessing, a great aid for their back aches, as a well-constructed corset can provide better support than a back brace. However, chances of your corsetiere also being a doctor are quite slim; I certainly am not. Please be very careful with any attempts to self-medicate via corsetry. If you wear your corset too often, the muscles of your core can weaken; make sure they are still getting exercised some other way if you want your body to be able to support itself uncorseted. (You do.)
Other, lesser concerns include chafing or poor ventilation to the skin, which could cause a rash. The former is generally easily avoided with the aid of a proper fit, and the latter is generally only a concern for those with particularly sensitive skin who live in warmer climes.
Do I have to sleep in my corset?
Some waist trainers will sleep corseted. While the idea of passively training sounds fabulous (I can hear the infomercials now: "Reduce your waist line in your sleep! Call 1-800-CORSETS to find out how!"), you may not find it comfortable and it is by no means mandatory. If you do sleep in your corset, you may want a different style, fabrication, or waist measurement in order to stay comfortable.
How is a waist training corset different?
Corsets worn for training or tightlacing are under more stress than those for casual daywear. To prolong the life of your corset and provide additional support, there are several options. Double boning would be my first recommendation. To reinforce the additional bones, flossing can help anchor them in their channels, or external bone casings will help prevent poke-throughs (and leave room for an easy fix if they do occur). Don't wear your corset directly against your skin; your body's natural sweat and oils will speed the deterioration of the fabric and you'll also have to take it to be cleaned more often. If engaging in physical activity, wear a short hipped underbust style to allow for greater freedom of movement, or take your corset off completely to prevent warping the bones and stressing the seams of the fabric. A cotton fashion fabric will be stronger and longer-lasting than silk, and you can upgrade the strength to an organic-cotton/hemp blend, which is much stronger than cotton alone (available only in black herringbone). Coutil is also available as an upgrade for fashion and/or strength fabrics.
Own all the corsets!
Ideally, you should have two or more corsets to rotate through. Like a bra or a pair of shoes, a corset will wear out much faster if you don't give it a break between wearings. Remember that Victorian corsets, worn daily, were often under warrantee to last only a year at most: a corset worn for daily training will not have the same lifespan as one worn for only for special occasions. You may wish to select corsets in varying silhouettes, colors, and even sizes, to broaden the number of situations in which you can wear your corset. I mention sizes because you may have days when you feel committed to the idea of training or wearing a corset but don't feel up to lacing down to your normal measurement. It's better to wear a slightly larger corset than feel the pinch of a too-small corset with an overlarge lacing gap - no one but you will know your waist size.
Waist Training 101 - Blog post on The Lingerie Addict by Marianne Faulkner of Pop Antique.
Beginning a Waist Training Journey - Blog post on The Lingerie Addict by Marianne Faulkner of Pop Antique.
I Want to Start Waist Training. Help! - Blog post by Strait Laced Dame.
Corsets & Health: Should You Be Worried by Corseted X-Rays? - Blog post on The Lingerie Addict by Marianne Faulkner of Pop Antique.
Tightlacing 101: 4 Myths about Waist Training with a Corset - Blog post on The Lingerie Addict by burlesque artist and corsetiere Tristan Risk.
On a Waist Training Journey, It's OK to Take Rest Stops - Blog post on The Lingerie Addict by Marianne Faulkner of Pop Antique.
Corsets and Sleep - Blog post and video on Lucy's Corsetry.
Great Corset Blog Posts - Pinterest board indexing an array of educated posts about corsetry from a variety of authors.
Lucy's Corsetry - Informative website about corsetry.