The Uki-otoshi (Floating drop) Waza is used to pull an opponent and throw him down the moment in moves forward.
First, Tori (Player executing technique) induces Uke (Player receiving opponent’s attack) to take a step back, then, in the moment when Uke brings the retracted foot forward again, Tori pulls him strongly forward to destabilize him.
At this point, Tori may either bend one knee, or lower himself into a posture with one knee on the floor while destabilizing Uke in the forward direction.
If the kneeling posture is used when destabilizing Uke, it is critical that Tori maintain a proper posture. The Waza will not be effective if his hips are lowered to the height of his heel.
Although this is a Te waza (Hand techniques), it is important to understand that destabilizing the opponent depends both on the hand technique and the body motion.