There is a cure!
But, of course, it comes with a lot of work LOL Life is never easy!
I will steal from a wonderful trainer who explained the Excito-meter to me. Basically, when the dog is relaxed, the Excito-meter reads low. As they are stimulated, it rises and rises until it is in the red, the point of no return where the dog is too excited to behave (the time when they tiddle). However, you can learn to control the dog's Excito-meter.
Start by teaching your dog how to "watch me". Basically, they just have to make eye contact with you. It gets there attention. To do this, say watch me and bring a treat up to your eyes so the dog looks up. When they look, click and give them the treat. Repeat, repeat, repeat.
Now after you get their attention, start doing simple obedience like sit and down with their attention. Keep everything calm and focused. Do this as a quiet time of the day.
Now that you have the tools to get the dog's attention and focus it, get them a little excited and calm them down. Once you are super-successful at that low level on the Excito-meter, get them up another notch and bring them down. Keep going until you have to use you coming home or somebody coming to pet the dog as the stimulus. At this point, you can set them up where the friend only pets them if they are in a down or a sit stay.
Getting the Excito-meter reading to drop will help to decrease those pesky tiddling incidence. If you can keep them out of these situations as much as possible while you are training, that would be good.
If your dog is having problems with submissive urination, I would go about it a different way.