The base ring sits behind the testicles and around the base of the penis. Getting this measurement right is essential because a ring that is too tight can cause discomfort or circulation problems, while one that is too loose may allow the device to move or slip.

Take the measurement while you are completely flaccid and relaxed. Use a soft measuring tape around the area where the base ring will sit.

The tape should sit snugly, but it should not dig into the skin or cause discomfort.

Measure from the base of the penis to the tip while completely flaccid and relaxed. Do not stretch or pull the penis forward while measuring. You are looking for your natural flaccid length, not the longest measurement you can achieve. The cage should allow the penis to sit comfortably without excessive empty space at the end.

Measure around the widest part of the penis while completely flaccid and relaxed.

Use a soft measuring tape and keep it comfortably against the skin without pulling it tight. This measurement helps you choose an appropriate internal cage diameter. A cage that is too narrow may cause unnecessary pressure, while one that is too wide may provide too much movement.

The gap is the space between the base ring and the cage once the device is assembled.

This space needs to be secure enough to keep the device in position without creating excessive pressure or pinching. Too small a gap may cause discomfort, while too much space can affect how securely the device sits.

Your measurements can vary slightly depending on temperature, activity and how relaxed your body is, so avoid relying on a single measurement. Measure while completely flaccid and relaxed, ideally at different times, and repeat each measurement a few times before making a decision. If your results vary, use them to understand your normal range rather than simply choosing whichever measurement is smallest.

Measurements are a starting point, but comfort and safety should always come before appearance or restriction.

Check the manufacturer's sizing information carefully before choosing a device, as dimensions can vary between designs and brands. A properly fitted cage should feel secure without causing pain, persistent pinching, numbness, discolouration or circulation problems. If something does not feel right, remove the device and reassess the fit rather than trying to tolerate it.