You can use Immodium to get through a situation like that. I wouldn't recommend relying on it on a regular basis, but used occasionally to get you through a situation where you have to travel or attend some lengthy function where you can't use the restroom or don't have access to one is okay.
You can also try l-glutamine supplementation. It's good for gut healing and is effective for stopping/controlling diarrhea. High doses of probiotics can help calm things down, too.
Diagnosed with ulcerative colitis spring 1999