I have posted in other threads about the comfort details of butt plugs, and I feel this thread deserves a little clarification.
Butt plugs have 3 primary features: the bulbous head, the long neck, and the handle. For comfortable butt plug wearing, especially for longer periods of time or physical activity, a long skinny neck allows the sphincter to close down and securely hold the bulbous head inside after being inserted. The handle is often T shaped to more neatly nest between the butt cheeks. The goal here is to wear it and enjoy the feeling of it inside, no matter the size or weight.
Anal dilators are often lumped together with butt plugs, however, they are different in many ways. Dilators are often sold in a set of 5. Both the bulbous head AND the neck progress in size as you move from smallest to largest. The head and neck may even be the same size, looking more like a continuous shaft. The handle is not necessarily T shaped, but often a full ridge all around the base.
While a butt plug is designed to be inserted and enjoyed in its own way, dilators are intended to be used as a training progression. A first time user might slowly insert a size 1 (approximately the size of an adult thumb) with plenty of lube and massaging. They might keep it in for 5 or 10 minutes, allowing the sphincter time to relax and adjust to the sensation of being held open. The user then might remove it, and insert it again, seeing if the sphincter is more agreeable to allowing it in and out with less resistance.
If all goes well and feels good, the user might repeat this process with the size 2 dilator. Use lots of lube and go slow. The process of learning to relax and accept objects into ones anus takes time, both in a single session and over the course of many sessions. Learning to relax and stretch a muscle is similar to slowing improving at yoga. Take baby steps to avoid injuries. While the first few days may only utilize size 1, eventually the training session will include sizes 1 and 2. After more days of practice one may use sizes 1, 2, and 3. Beginners may prefer to explore by themselves at first as it gives them complete control over the insertion process and the decision of if and when to try the next size up.
Some users might reach a point where they can skip size 1 and their daily session begins with size 2 and then progresses up to 3 and 4. Everyone is different and part of the fun is practicing and learning about your own body.
As this relates to sex, one might want to use the dilators as a part of foreplay, with a partner or alone before the partner joins. Having the anus well lubicated, relaxed, and comfortable holding a size 3 or 4 is a great precursor to anal sex.
Some users may find that over time, their daily session requires only sizes 3, 4, and 5. If the goal of penetration with a partner during anal sex only involves an item that is approximately the same diameter as a size 3 dilator, they may be able skip the use of dilators during foreplay, and simply use lube and massage to ease them into the main event. If anal sex is enjoyed frequently, the use of the dilators may taper off and no longer be needed. If anal sex is only experienced occasionally, one might want to keep some practice sessions every now and then so as to not loose the gains that have been made.
(I’m not related to these companies in any way, just providing a sample image for reference.)
Typical anal dilator set:
https://www.rainbowdepot.com/Ms-Expansion-Trainer-Anal-Dilator-Set_p_142060.html
Typical butt plug:
https://www.bvibe.com/snug-plug.html?136_323&92_33