A belt like this is the best solution. You need something to pull the ring back. It doesn't even need to be very tight.
I was able to jerry-rig something out of an old waistband from some underwear I would have otherwise just thrown away. Just cut the waistband off, thread it through the ring, and wear it around your waist like normal. The elasticity makes it not perfect, but hey it's free to give it a try.
For those who are curious it looks something like this but without the leather strap: https://www.amazon.com/Fetish-Fantasy-Extreme-Chastity-Belt/dp/B00BDQ0ETC