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.
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
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
For a simpler example of this kind of interactive predicament we'll need a spreader bar
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.