The sad fact is that what might work for some rapist, will turn another into his first kill. There really is something to be said about gut instinct.
One thing, as has been mentioned above, is to NEVER go to a second location with anyone. If they confront you with a weapon to try to get you into a vehicle, this is your chance to scream and make as much noise as possible. You very well could be injured while trying to make your escape, but if a perpetrator is trying to get you to a second location, your chances of making it out alive decrease dramatically.
Try to make yourself seem as a person to the perp. Try to talk to them about your personal life and his. However, if you see that this angers him, try a different tactic.
You pretty much have to be able to try different things in a situation like this to try to stay alive. I know that this will shock people, but it really is a hard fact. You are most likely going to be raped. If a perp has you isolated, and wants to rape you, it could very well happen. But, if you can save your life, that is the ultimate end result. So, we have to ask ourselves if we can survive, having been assaulted. No case will be the same and a rapist who has raped 10 women can finally kill the 11th.
Going back to the OP about urinating on someone to avoid a rape, I think that this might work some of the time, and the rest of the time it would infuriate the rapist into doing something worse to the victim.
Trust your gut and prepare/practice for the event, should it ever happen to you.