How do I get a tick off my dog's butthole?

Ticks, as we know, go for sources of heat to feed on their host's blood. Well, this one decided to go for my dog's butt. It is actually on the butt opening, on the left side. I have tried tweezers to get it off for about half an hour, while she was on her side. I rewarded her when she put here head down, and scolded her when she nipped me curiously. As you can probably tell, she doesn't like anything messing around down there. Can you please tell me a way to get it off? It just attached, so it isn't filled with blood, but it will be. I know there will be someone saying I should wait it out, but my dog is very uncomfortable, and I don't generally want a tick there on my dog. Hopefully you can help, thanks!