Cock rings are usually made of silicone so they can be stretched over the penis and testicles to (a) help maintain an erection, (b) make said erection harder by limiting blood flow, and (c) if it has a vibrator feature, stimulate your clit during penetrative sex
Best for: Coupled penetrative sex, masturbation where you also want to focus or need more concentration for maneuvering an internal vibrator, assisting internally while your partner goes down on you.
Not great for: Just clit masturbation. They’re fine and you might like it enough for just clit masturbation, but generally speaking, you don’t want to be tied to a toy for all your clit masturbatory needs.
Tips/how to use: Try using one on your clit during missionary or doggy while your partner enters you vaginally. You can also hold it in place during girl-on-top as it’s less likely to fall out of your hand while it’s attached to you.
Flatter-shaped panty vibrators are usually clitoral (like 95 percent of them are such, but you’ll find a few that also have small internal components that can be worn inside you), that sandwich between your underwear and your vulva for clitoral stimulation.
Not great for: Coupled penetrative sex. They’re way too bulky for you to feel the vibrations from the toy while being penetrated. While you can always slide your undies to the side to still “wear” underwear while having sex, the bulkiness of these toys mean you can’t really slide to the side to allow entry for your partner while still feeling the vibrations.
Tips/how to use: Give your partner the remote (or if you have a model that lets someone control it from anywhere in the world, get them to download the app) and give them the controls while you’re subject to their whims.
Not great for: Blow jobs or hand jobs (you won’t reap the benefits of vibration on your hand or mouth) or use as a standalone clitoral vibrator (there are way more efficient options for that)
Tips/how to use: With your partner wearing one of these (you can 
start with it just on the shaft of his penis, or try stretching so it also includes his balls), ride him cowgirl so you can control the position of the vibrator on the ring so it hits your clit just right.
Blowjob sleeves are p up penis masturbation through a bunch of different internal textures inside the hole. The idea is that the different patterns and textures inside stimulate the penis in a variety of sensations for a fancier version than your hand or mouth. Must be used with lube!
Tips/how to use: Ready for a game-changing blow job hack? Slide a smaller blow job sleeve inside out over the head of a Magic Wand or internal toy and lube it up for a new sensation on your go-to toy. For penises, use a blow job sleeve with some hand or mouth assistance to make a blow job even better. You can snip the end of a Tenga Egg so it’s a full-on sleeve, and use it on the base of his penis while you use your mouth on the head.
Not great for: Clitoral masturbation (it’s not going to do anything for you) or partnered penetrative sex (too much material in the way)
Butt plugs look like mini dildos, usually way shorter, and with a flared base. Always get a flared base, because you want to make sure you can remove it easily without it getting “lost” and sucked up inside your anus. They come in a variety of sizes (smaller for beginners and so forth) and can be vibrating, weighted, made of glass or metal for temperature play, and so on. Some, like the b-Vibe, even have small beads on the stem, to stimulate the sensation of getting a rim job.