A dunk can be seen as being dunked into something. You might hear someone say “I just dunked my cookie in a glass of milk.” It’s the idea of a solid being put into a liquid. This is why the dunking tank is called the dunking tank at the carnival because at the will of whoever is throwing the ball, a person is being dunked into the water based on how well they can hit. The other definition of dunk is the sporting move. When a person goes up to a basket in the game of basketball, and jumps slamming the ball through it without having to just throw it in. This requires great athleticism in order to accomplish and even great mental athleticism when it comes to dreams.
If you have a dream in which you are in a dunk tank or where someone plans to dunk you in something it means that you are being taken advantage of, at the earliest convenience you will be betrayed by whomever it is that you are helping in real life. On the other hand if you dream that you are going to dunk yourself in water it means you are ready to try new experiences even if they might seem scary and out of place because you are fearless. This will serve you well later on in life.
If you dream that you make a slam dunk, then this means that you have just achieved something great and are thinking about it. You are still patting yourself on the back mentally for your stunning achievement. This is a good thing. But remember not to let it go to your head too much or else you might start to get too conceited.