Urinal cakes are designed to fight odor and are often small and placed on the bottom of the urinal. They're not meant to be targets. If you hit them, they might create splash back and deflect urine spray in your direction. Change the angle of your stream. Don't hit the urinal dead on. The splash back will be worse the closer it is to 90 degrees. Instead, try to hit the urinal at a soft angle -- less than 45 degrees. Some urinal inserts and splash guards are designed to absorb the impact of your urine stream to reduce potential splash back. Shoot for these, especially if you can pee on one that bends upward so that it is vertical and so you can hit it at less than 45 degrees. Splash back is greatly increased when your urine hits a surface at a sharp angle and from a great distance. After a few inches, your urine starts to break up into droplets. These droplets create more splash back than a solid stream of urine.  Distance matters because your stream will start to break up if you are too far, and you will have a higher chance of creating splash back. In addition, your urine picks up a lot of velocity the farther you stand from the urinal, resulting in more splash back. If you can impact that porcelain before stream breakup occurs, you will be in good shape. While you may not want to be too close, you definitely don't want to be standing too far away. Generally, your stream will begin to lose coherence and power after about six inches from your urethra, so take this into account when you pee. Remember though, there is no "magic" number when it comes to how far to stand from a urinal, because each urinal is different, every person is different, and everyone's comfort level is different. When you’re done, don’t shake too quickly. This might cause your urine to fly through the air or it might hit the urinal and you could create splash back by accident.
Avoid hitting the urinal cake. Hit the wall of the urinal at a gradual angle. Aim for splash-reducing urinal inserts. Stand closer (but at the right angle). Don't stand too far. Avoid “shaking” too briskly.