Multiball Training
Loopy is practicing the forehand loop down the line against underspin. Sasha is serving the balls with a consistent rhythm which lets Loopy get into a groove. This builds accuracy.
You can use simple repetitive drills to work on a particular shot or elaborate sequences to simulate a real point. In this sequence, Loopy tries to place the ping pong balls towards the right side of the table. Now, he's doing the same sequence aiming for a different placement.
Always make sure you move correctly, no shortcuts. In the drill, you know where the ball is going. In a game, you don't. Multi-ball practice will get you exhausted quickly. How quickly obviously depends on your condition. When you feel you're losing control over your accuracy, stop and regroup.