How do you dunk?

Which buttons do I need to press to dunk?

Sprint+Shoot.

Go into the game, and select - Game Modes > Practice > Training Camp

From here you can train on all moves as much as you like with visual examples of controller.

Sprint towards the Rim and Dunk, make sure though it is a free lane since if there is a defender I believe 75% it is a layup.

I'm in free style practice mode and when I sprint to the rim and press shoot, all I get is lay-ups!

Ok...Figured it out..U have to hold the sprint button and not let let go and press shoot..why the *uck would they get rid of the dunk button?

you do know this isn't nba live right? i mean i'm just assuming here because nba live had a seperate dunk/layup button

Correct. NBA Live had a dunk/layup and shoot button (and in the case of NBA Live 07, a dunk, layup and shoot button), 2K did not. They do have the shot stick though, which you can still use this year if you wish by holding the left trigger. That'll switch the right stick from dribbling moves to shot stick controls.