Well, probably you've heard about Mister Poll. If not I can only tell there are really lots of polls there, and you can guess there some about peeing and pants peeing, however there are too many. Many of those are short and not interesting at all. So I decided to select some best ones out of those all.
Normally there are two typical polls - contest polls so that you are doing some kind of challenge while holding and simply asking questions about different stuff. I'll start with general polls:
XXL Pee Poll
Ultimate Pee Poll
Peeing Pants Preferences
Random Poll About Peeing
What would you do if......
Pee in your Pants?
how do you pee and poop your pants?
Now here are some contest-polls:
Desperate to pee/poop?
take if you have to pee
Pee holding and ways to hold pee
how bad do you have to pee? (!)
31 Questions to see how long you can hold it! (Girls only)
Need to pee really bad? TAKE THIS POLL
Do you need to pee?!
Take this poll if you really need to pee
And finally once I came across one vid on YouTube about girl filming herself while doing one of such polls: 195ws2 (click on the name to watch).