Come into a plank position (the top of a push-up), and roll to your left side, allowing your feet to roll, too, so you're balancing on the outside of your left foot and the inside of your right. To advance this move, stack your right foot on top of your left.
Reach your right arm toward the ceiling and lift your waist away from the floor to make your obliques fire away. Press your left inner thigh up into your right inner thigh; this helps stabilize you even more.
To take pressure off of your wrist, press your left fingertips into the floor.