Tiptronic gearbox
 

I'm wondering, that can i put my tiptronic gearbox from D to N, while crusing, and not pushing the break, to rev the car, and put it back to D?

Your car is able to do this? Or you want your car to do that? If its number one, thats bad, you have some kind of lock that is not engaging. If you want to rev your motor and drop your car in gear go buy a crappy mustang. You're going to screw up your trans.

i havent tried yet, but i dont want to try it, because what if i broke it. the multitronic gearbox a4 can do this anyway

That's....definitely not a good idea..
You could hold the brake while revving the engine, since you have a torque converter, but jamming it from N to D will mess everything up. Still, it's not the most healthy thing to do for your car.

Why do you even want to think of doing something like that?