"Now - I want you working three to a training dummy," with a sweep of his wand, the dummies obediently spread out across the room, "and I want you to practice not only trying to cast the basic combat jinx, but also any combative spell you can think of. Linking them together is often easier. The wand movement you’re looking for, is a kind of sharp whipping motion," Harry drew his wand back, and snapped it forward again, an angry red bolt leaving his wand tip and colliding with the nearest dummy with a smack, making it rock back sharply, "if any of you feel confident too, try taking the place of your dummies and practicing your shield charm - start with sparks. Now, it’s your turn."