Place bananas in a blender with about a 1/4 cup water. (The water is there to make the bananas mushy, so add more water if needed) Pulse the bananas until they are mostly mushy looking. Add all of the pineapple chunks to the blender as well as half the liquid in the can. Pulse again until mixed. Now add the coconut and extract. Pulse this until blended and serve.
You can add less pineapple if you find that there is too strong of a pineapple flavor for you.