Lobbing is the last resort to survive a point. You do it when an opponent has driven you so far back from the ping pong table that you can no longer mount your own attack. By playing the ball very high and giving it a lot of spin you make it difficult to smash and you hope the attacker will commit an error.
Let the ping pong ball drop close to the ground and when you hit it upward give it a lot of topspin and, if possible, different types of side spin to assure an uncomfortable bounce on the table. Stay back and recover to the center of the court because you'll need to be able to cover both wings.