There are various versions of this on the internet. The K-Ring is a simple and fast ring intended to be put onto special part of male anatomy (the one which can grow significantly). There are lots that can be printed at home with a 3d Printer.
It is placed on the anatomy when flaccid and acts as a punishment if the subject gets aroused as then this little cruel ring’s pointy bits (those little pointy cones) press into the skin delivering serious amounts of sufferings to the subject.
The cones should be blunt enough to ensure that they cannot puncture the skin. Mostly the rings are designed to be used on the 3.5-4 inch circumference but if like Master Xoobs that’s a little too small, then it can easily be adjusted in design so that it. is held together by a strong rubber band. This allows expansion and pain without bruising.
These are similar to the Spanish pony for her and are are certainly not for long-term wearing – I prefer the rubber band technique anyway as it can be released almost instantly with a sharp blade (but be careful where you are cutting!!)