I know that you're not playing this game anymore but I can still give you ideas for the next time you play it, how about that?
Usually I don't play dirty truth or dare games, but when things start to get dirty, usually the questions asked are "I dare you to kiss so and so", "tell me the time when you did (insert naughty action here)", "I dare you to (perform naughty action) in public and video tape yourself doing it", or "I dare you to (perform naughty action) right here, right now". You can always think up stuff along those lines to make things more exciting I guess is the right word to describe it.
As you can probably tell, I don't really do this so these are just some ideas I have from the top of my head or some that have been done before by my friends.