1) Gather Your Supplies. You'll need a piece of string and a ruler to get your measurement. We recommend using a string instead of trying to use a soft tape measure
2) Measure. Wrap the string around your penis and behind your balls. Mark the string where it meets. You want the string quite snug. You should be able to just fit a finger between your skin and the string when you're soft. And it should be comfortably tight when you're hard so that you can't fit in a finger. You may want to measure both soft and hard to double-check your size.
3) Determine Your Size. Measure the distance from the end of the string to the mark. This is the circumference. Divide that number by 3.14 and that will give you diameter which is how we size all our rings. Ex - 6.25" divided by 3.14 = 1.99" which would be our 2" cockring.
Tips - If you're between sizes, go down to the smaller size for a snug fit or go up for a little more relaxed fit. Measure twice! Due to the intimate nature of these rings, we can't accept returns or exchanges.