Stand sideways next to a dumbbell rack (preferably) and place one hand on the rack while holding a weight plate on your chest with your other hand. This is your starting position.
Squat down by bending your knees and dipping your back down as if you want to lay down. Go as far down as you can. Once down, return back up to the starting position. It's OK if you cheat a bit to help yourself up by pushing off with your other hand (this is why it's called a "sissy" squat).
Finally, repeat the entire movement for the desired or prescribed number of repetitions.
Perform this exercise in a smooth and fluid motion
Don't do this exercise if you are a beginner
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or place a heavier weight plate across your chest.