The Moeller stroke is really simple, and can make a HUGE sound without much effort. Imagine there is a string connected to your wrist. Lift the string up directly upwards. This will make the hand go down, and also the arm go down, making the wrist the highest point of the arch. Then just drop your wrist freely, and it will make a HUGE noise.

When you do this stroke, lift your wrist up very fast. This will make the stick go farther back than your wrist, making a louder sound.

       Remember, don't put much pressure in your wrist when hitting the drum.

Watch this video for more info here.