With predicament bondage the sub is not simply bound helpless, he is bound in such a way that he can only move between a limited number of, or range of positions. Thus presenting a predicament for the sub. These predicaments usually fall into one of two categories. Either, the sub must choose between two different types of pain, or must endure pain to get pleasure. The third but less common possibility is more interactive: while the top is "distracting" the sub, the sub must be actively doing something to avoid pain or to receive pleasure. I'll go over an example of each. After all, when it comes to kink, nothing quite beats learning by example.
But first, precautions!
Always bind a sub in such a way that no serious harm will come to him if he were to pass out, slip, get knocked over, lose his balance, or otherwise fall or collapse. Most standing bondage is done with the sub's arms tied to ceiling hooks, so if anything happens most of his body weight is held up by his arms, and not by anything else that might be tied up. For example, if a sub locked into a cock and ball pillory were to fall over for any reason, there's a good chance he would castrate himself. However, if he also had his arms tied to ceiling hooks with only a couple inches of leeway, he'd only give himself a really good stretching and would live to play another day. The other important thing is to never leave a bound sub alone. Aside from the rare random events such as a fire breaking out or a burglar breaking in, things can go wrong. Things you couldn't or didn't imagine. Things that need immediate attention. Perhaps when struggling your sub will get some rope trapped around his neck, maybe something will poke where it shouldn't. These precautions should be taken with any form of bondage, but are extra important when playing with predicament bondage, since there's a lot more room (and a lot more reason) for things to go wrong.
The cock and ball pillory I linked to above has an adjustable height, which makes for a good first example. Have your pet stand as tall as he can on tiptoe, adjust the pillory to pull up lightly on his balls at this height, and only lock his balls into the pillory. As his leg muscles grow tired, he will try to relax them a little, and begin pulling on his balls. As the pulling becomes too much he will go back to standing on his tiptoes. Thus alternating between straining to stand tall and pulling on his own balls. If he can stand pulling on his balls while being flat on his feet, then you should raise the height of the pillory so he's not able to rest like this. Also, as I mentioned earlier, make sure your sub won't rip his own balls off if he were to fall or collapse. Again this can be done by suspending his arms above him so that his weight will transfer to his arms if something were to happen. Aside from putting in ceiling hooks, another option would be to bind the sub's arms to the top of a sex swing frame, which by design can hold the weight of two people. Of course, all of this, while incredibly sexy to watch, can be expensive and a bit of trouble to set up.
For an easier example, start by tying or otherwise securing your sub to the bed, face down but with his head and shoulders over the edge of the bed. Make a noose and tighten it around his balls. I'd also suggest putting a butt plug with a flared, flat base into his ass. Bind his hands together behind his head. Run the lose end of the noose up and over the plug, and tie it to his bound hands. Tighten it while having him stretch his arms back as much as he can. As his arms tire, he will try to rest them, and in doing so, wiggle and push on the plug, and pull up on his balls. A sexier version of this is to skip the balls and plug entirely and use an anal hook. Insert the anal hook into your sub's ass and then using another piece of rope tie the hook to his bound hands. Now, as your sub's arms get tired and he has to rest them, he will fuck himself in the ass. Resting his arms will pull the hook in, and when holding his arms back the hook will slide back out. It's actually quite a site to behold. Most anal hooks have a ball on the end. This not only makes them stay in better, but they are safer as any pulling or tugging is distributed on a wider area. Personally I think double ball anal hooks, like this one or this one, are more fun.
Another common form of predicament bondage is where the sub willfully causes themselves pain to get pleasure. My favorite example for this type of predicament starts, as so many of these do, by noosing up your sub's balls. Attaching the other end to a fixed object, such as a door knob, and adjust the length so that the sub has to pull on his balls to penetrate you. You can slowly move away so he has to pull harder and harder on his balls. I've written about this in more detail here in my post about sex. If you're in the no sex camp, and your sub really loves going down on you, you can do the same thing but have him pulling on his balls to eat you out. It's fun to see what a sub will endure for pleasure.
This same kind of predicament is more commonly done with women using a vibrator. Bind the sub's hands and clip or otherwise attach her nipples to something above her, towards the headboard if laying down or hooks if she's standing, and place the vibrator just out of reach. The sub has to pull on her nipples to reach the vibrator. This will work with most males as well since most can come from a vibrator too, but it often takes a stronger vibrator. Either way I recommend the Hitachi for this. If you are trying this with a male sub, his balls are often substituted in the place of nipples, but there's nothing wrong with some nipple fun. As the sub gets more worked up, you can adjust things so he or she has to endure more to finish.
The last group of predicaments are more fun for me because the top is directly involved. I'll start with a more complex example. For this to work, you need to devise a pulley system. You can throw a rope over the top of a sex swing, or run it through a ceiling hook. The important part is that when you apply weight to one end of the rope, it pulls up on the other end. Next you'll need a dildo that has balls, or at least a flared base; this includes pretty much all strap on dildos. For this predicament, I find that a very realistic dildo is more fun, but like I said, any dildo with a flared base will work. Next, we need what's called a clip or clothespin zipper. This is just a series of clips or clothespins connected by a rope or string. (The name comes from the sound it makes when pulled off quickly.) And lastly, we need a bucket. Start by securing your sub so he can not move, face up. Attach the zipper to his genitals. Put the dildo in your sub's mouth and tell him to hold it there. Tie some rope around the dildo such that pulling on it would pull it out of the sub's mouth (this is why the flared base is important), and tie the other end to the zipper line. Make sure the rope is taut. Then run some rope from the dildo over whatever frame or pulley system you've set up, and tie it to a bucket hanging from the pulley. You can do this with two separate ropes, one going from the zipper to the dildo, and one going from the dildo to the bucket. Or just one long rope to attach all three together using a an Alphine Bufferfly Knot to hold the dildo. When you put weight in the bucket, the sub will have to hold onto the dildo or the bucket will lower and rip the zipper off him. Or as a more artful way to describe it, the sub has to suck cock to avoid pain. Make sure there's enough weight in the bucket so when the dildo finally comes out of your sub's mouth, the bucket will come falling to the ground and rip the zipper off. Given enough time the sub will eventually lose hold of the dildo, but a lot of fun can be had in speeding it along. One approach would be to add more and more weight, seeing how much cock weight he can suck. But a much funner thing is to try and make him cry out and drop the dildo. Just remember to keep out of the way of the zipper line, as you never know when it will come flying off. Once you have what you need to do this, you can set up the predicament fairly quickly. And the list of things you can do to distract a sub in this situation is virtually limitless!
For a simpler example of this kind of interactive predicament we'll need a spreader bar and a collar (more collars can be found here or here) or cuffs. Simply attach rope to your sub's balls, down and around the spreader attached to his ankles, and then back up behind his back and to his collar. If you have cuffs instead of a collar, cuff his hands behind his head and tie the other end of the rope to the cuffs instead of the collar. In this position, as the sub tries to sit up, he will pull on his balls. To make sure he doesn't bring in his feet, you can attach the sub's ankles or spreader to a footboard or bed frame. In this predicament, when you hit his balls he will attempt to curl up to protect them, but instead of protecting his balls, he will just end up pulling on them. The reflex is nearly impossible to resist. Even in kinky porn where you know the guy is loving getting his balls beat, you'll see him bend in for protection now and then. This is a bit more specific to CBT (Cock and Ball Torture), but is a fun and easy form of interactive predicament to set up.
Predicament bondage is actually a lot of fun if you're good with rope. It does however tend to take up more time than other, simpler forms of play. And it can be a bit frustrating to set up if you're new to it. But it's one of those things you can learn pretty quickly, and in my honest opinion, is worth learning. Predicament bondage is great for when you want to have some fun, but aren't sure how to spice things up beyond the norm. While the last few examples I gave are designed with "intervention" in mind, you can usually work some form of play into any type of predicament bondage if you're looking for a more hands on game.