If you ever have to go to the bathroom really bad, like maybe you're in your car and you're 10 minutes from the next rest stop, start stroking your junk. Being sexually aroused blocks out your need to shit.
Well, it works for me, at any rate.
This may not be the best idea if you're on public transportation.
Also, be careful when you're driving. If you end up crashing into the median you'll be found in the worst of all possible situations: with your dick in your hand and your underpants full of dookie. And then it will work its way around everyone who attends your funeral that you got turned on by shitting yourself. Then someone will be like, "Ah, damn, I wish he hadn't died. I have the doubly-perfect nickname for him now." And everyone will be like, "What's that?" And he'll say, "Skidmarks." And everyone will be all, "RIP, Skidmarks."