Butt plugs may not be the most used sex toys, but that doesn't mean they aren't extremely fun! But, what is a butt plug? And, how can you find the best butt plug. Butt plugs, however, do exactly what you'd imagine: They plug up your butt. A butt plug's main duty is to make you feel good: "The anus can be. From a glass plug to a remote control vibrating butt plug, we've laid out a handful of our absolute favorites along with some recommendations.