First, your top priority should be to make sure bondage and kink is always 100% safe, sane, and consensual.  Never leave the room with your sub in bondage, always keep keys nearby, and when using rope, keep a scissors with you at all times just in case a quicker release is needed. Always assess what your sub is capable of before doing anything like this with him, based on his body type and endurance level from previous sessions. If you don’t think he can handle it, don’t do it! For more strenuous bondage such as some predicament bondage, always keep a chair nearby or something that will allow the sub to relax quickly if needed. Bondage is no fun for anybody if someone really gets hurt.

Choose a height where the sub has to squat down a bit, not allowing him to stand up straight.

Then you can take one end of the handcuffs and lock it around both his dick/balls together.  Pull the other end back between his legs and cuff that to the eyebolt, file cabinet drawer handle, a padlock that is locked to a custom closet wall bracket, or whatever you have around that will work.

This one is very adjustable depending on the height used. Do you want your sub to be able to kneel somewhat awkwardly/uncomfortably (or try really hard to kneel thinking he'll be able to, and fail)?

Do you want to prevent him from standing or kneeling on the floor? The height you choose will determine his options. If you have a sub that loves a challenge or tends to get cocky about being able to handle anything, this one should definitely challenge him!

Doms and subs:  If you decide to try this on your sub, or your Dom does this with you, add a comment to let us know how it went.

Instead of cuffing your sub’s balls to the eyebolt in the wall/file cabinet handle or whatever anchor point you chose, you can have him lean forward with his back to the anchor point and his hands reaching between his legs, then cuff his hands to the anchor point that way. Then with a set of leg irons, cuff his feet together. It doesn’t matter how close or far apart his feet are as this part is only to prevent him from stepping out of this one by lifting one leg over his arms and turning around. This position will still keep him fairly low to the ground if that’s important to you, without cuffing his balls.

Or, same as above, but use an anchor point that’s a bit higher up to keep your sub on his toes (literally). This way, he’ll be straddling his own hands which are pulled between his legs and cuffed to the anchor point. It could be fun watching him lift his right foot up and lean to the left with his left foot flat on the floor, until he gets tired of that. Then he’ll lean to the right and do just the opposite, back and forth until you release him.

Better yet, take #2 above (or even #1) and lock his dick in a chastity cage. His hands will be locked right under his dick in #2 above. He’ll probably be so horny and wanting to stroke his dick, but can’t because it’s caged. ;-)