Defensive spells.

"We'll practice the Disarming and Shielding Charms", you say. "If you can't fight your opponents, disarming them will definitely give you an edge. And being able to block spells will always help."

You stand next to Neville, and point your wand across the room.

"Repeat after me", you say. "Expelliarmus!"

Neville repeats what you say.

"Good", you say with a smile. "Now, Protego!"

When Neville repeats the Shielding Charm, you smile at him.

"Let's go for the real thing," you say.

You set up some cushions in two piles in the empty space in the front of the room, and stand in front of one. Neville hangs back, so you smile encouragingly at him, and he steps cautiously in front of the other pile of cushions.

"I'll do the charm on you first", you explain. "Then it will be your turn. The cushions will break out fall if anything bad happens."

Neville gulps, but you just grin at him again, and he calms down.

"Try to shield yourself from my spell", you suggest. "On the count of three: 1, 2, 3. Expelliarmus!"

Neville squeaks, and his wand shoots out of his hand. You catch it easily; your reflexes honed by years of being a Seeker on the Gryffindor Quidditch Team.

"You didn't even try!" you chide, handing Neville back his wand. "Now your turn to disarm me. 1, 2, 3."

Neville and you cast the Disarming and Shielding Charms, respectively, at the same time. Your wand jerks in your hand, but not nearly enough to disarm you.

"Not bad", you say, and Neville lets out a shy smile.

You continue in this vein for some time, taking turns to attempt to disarm the other. You notice, though, that Neville improves with each attempt. He even manages to shield himself from your charm a couple of times. The third time Neville shields himself from you, he gets a bit over eager. Rather than try to disarm you after the count of three, he casts his charm on three. You don't have time to raise your shield, and you feel your wand leave your hand. As if in slow motion, you see it arc over the space between you. At the same time, you feel the energy of the spell shoot through your body. You feel your body leave the ground, and be thrown meters backwards, past the pile of pillows you set up for a soft landing. Instead, you land on the hard stone floor. You hear a crunching sound, and your vision goes black.