"Alright guys, repeat after me: GO!"

"GO! » his students shouted.

"Tego!" he said. "Tego!" They replied. "Protego!" "Protego!" the class shouted. Then Professor Potter began to drill them individually on pronunciation.

"Yes, very good Mr. Quimbly. And you, Miss Beauchamp?"

Backchaining the pronunciation of spells, then the wand movements, and then finally summoning the will and visualization of the spell were all separate activities in Professor Potter's class. Spells, Harry knew, weren't something that could simply be learned out of a book.

"Very nice, class. Wands out please. Let's start with counter-clockwise circles. Remember to keep the motion in your fingers, not your wrist. Make them large and even. Good. Now smaller. Smaller than that Mr. McGonnagal. Very good."

Harry hopped up on his desk, giggles greeting his little show of athleticism. "Now watch carefully class." Harry pictured in his mind the bright white shield that he wanted in front of him, the simplest form of the Protego that the class would be learning today. He imagined the luminescent white that would give the shield a more defined form for his students to see. "Pro-" he began, rolling his wand counter-clockwise in his fingers, "-tego." The luminous white shield burst forth from his wand.

"Everyone please come around. That's right, a large circle. Observe the shield from all angles. Now, Mr. Hagrid, can you describe the shield for me?"

"Well it's white, sir."

"Yes lad, it's white!" Harry feigned enthusiasm. The tall boy was almost at eye-level with Harry despite the professor's current position. Harry unconsciously added a little twinkle to his green eyes to soften his features. "It's white and…"

"...and I can see through it a bit, sir." Hagrid's kid was by no means stupid, only a Gryffindor. To say the obvious and allow others their turn required a certain courage of its own.

"Very nice. Yes, the shield is white. Notice how the color pulses a bit in the center. Does anyone know what that means?" Harry looked at the students around him, internally scolding himself for already having asked the students to circle around to the back of him." No worries now, come around to the front and have a look. Miss Hardy?"

"It's the point of origin, Professor. You cast the spell from there, and that's where your magic sustains the shield." Harry noted her use of "the shield" instead of the more correct "the Protego." He wouldn't correct it just yet, since this was only the first shield his second-year DADAs were learning. They'd get plenty of practice with their essays, anyways.

"Very nice Miss Hardy, exactly. Watch again class so you can get a better idea of the point of origin. Look where my wand tip is now." Harry again cast the Protego the same way as he had before. This time he visualized the point of origin softening and slowly pulsing as luminous waves. "The Protego is sustained by my magic here, in the center. The Protego is a class 1 shield, which means…Mr. Finnegan?"

"It's multipurpose, sir, and it's point of origin is the same as the place where we sustain the magic."

"Very nice, my boy! Exactly. Multipurpose means the Protego will stop most hexes, jinxes, and charms. Its power to protect is equal to the power you put into it from the beginning as well as the strength with which you visualize it. Strong will, strong wand, strong word, strong spell!

"Now class, come around to the sides. Let's see if you notice anything new. Mr. Hargrove, stop flirting with Miss Hardy and tell me what you see!" Harry's eyes twinkled again and he gave a little laugh. After all these years teaching, he knew exactly how to keep the rambunctious lot in tow—public shame.

"Uh….sir? " Hargrove said, followed quickly by giggles from the girls and a quick blush from little Ellie Hardy. Oops. Had he thrown the gnome a little too close to the garden?

"The Protego, lad, what do you see from the side that you couldn't see from the front? " Getting nothing but a blank stare, he looked around for anyone who'd observed better than the besotted tyke.

"There's a little wisp, sir. Connected to the tip of your wand." Harry looked over his left older immediately into the eyes of Virgile Hagrid.

"That's it! The luminescence is the same, the color is the same, you can still see the pulse of the point of origin, but you can also see that little wisp there between my wand and the Protego. Can anyone tell me what that means?" Harry was glad he hadn't had to pull any harder to get the observation out of them. All things considered, that had been rather easy.

Mathias raised his hand. "It tells us how much power you put into the spell, sir."

"You mean more power and the luminosity of wisp would change?" The boy nodded. "Not quite, Mr. Ogden. Anyone else want to give it a —?"

"It shows us that there's a constant drain on your magic? " Ogden tried again. His interruptions usually weren't a problem, but Harry would have to start being careful. Good manners one minute, a Weasley the next. What's more, the boy was right.

"Exactly. How did you figure it out?"

"Well sir, there's a kind of flow to the wisp. I figured if it's only going in the one direction, it's gotta be pulling something out of you."

"Very nice! Take a point for Ravenclaw, Mr. Ogden. You're exactly right. I have to constantly will its presence. If you let up for a second —you'll lose it all.

"Very good class, please take your seats." Harry stepped down from his desk as his students went back to the stadium seating of the DADA lecture hall. The platform where he stood quickly emptied, and he silently sent the desk back to corner where it was usually placed.

"Now, on parchment, please describe the Protego. You'll find questions," Harry flicked his wand, "to help you with your descriptions on the board." Harry stepped around the class, observing what the students were writing and casting the Protego again when requested. "Now, in pairs, please compare your descriptions. Maybe someone noticed something new? The more complete your image of the spell, the quicker you'll learn it!" When the students finished describing the spell, they again compared it with the textbook description. Harry hated teaching with the textbooks. Hermione was the one who could learn everything from words alone — Merlin's dangling dirigiplums, the woman never even seemed to need to know how to pronounce the spell or even see it before casting it. For the giant's-portion of society, though, that method just wouldn't do. Seeing it done first, then reading about it usually gave students a better idea of what they could learn on their own and what they needed to learn from others.

"Very good, now everyone back to the platform please." Harry stepped onto the casting center of the hall, stepping into the middle with his students lined around him. He quickly covered pronunciation again and the wand movement. "Now class, close your eyes. Imagine your Protego manifesting before you. Feel the energy of your magic rise through your arm, through your wand, and then into the shield. Let's repeat that. Wands down, eyes closed. You're in the hallway. The blue orb of a Jelly Legs Jynx is coming at you. It's getting closer. Closer! Feel for your magic, and now send it out! Protego! Say it with me, Protego! "

"Protego! " "PROTEGO!" shouted Miss Beauchamp.

"Well done, Beauchamp! Let's not get too excited, though!" By this time the whole class had opened their eyes to look at Elise's blushing face. Harry loved her for it, though. Her mistake would give others the confidence to fail and try again. There was chuckling all around, and Harry gave the girl a little eye-twinkle to keep her spirit up.

"Wands up!" Smiles blossomed on the faces of each of his students. "Go at your own pace. First we visualized. Now let's visualize and add in the wand motion. When you're feeling comfortable, call me over, and together we can try the full spell."

Harry went around the room. Sometimes he added in words of support, sometimes he demonstrated the spell again, but mostly he just observed and kept the children on task. After ten minutes, a few students began to produce the first signs of the spell, and he started separating them out. Early learners went towards the center of the room where they could be observed by other students. After thirty minutes, Students who had completed their first Protego went to the Pillar, which Harry then charged with his own magic to send out the smallest of Stinging Hexes for students to block. After forty minutes, the whole class was succeeding at producing a Protego large enough to cover their chest. Harry took out other Practice Pillars and loaded them with Stinging Hexes.

"Alright everyone, that's time! Pens and parchment back in your bags, and I'll be see you next class. Now, every year after students learn the Protego, they think it gives them free reign to start hexing in the hallways. But just because your opponent can protect themselves doesn't mean you're justified in attacking them. If I hear of anyone attacking another student, " Harry looked pointedly at Mathias Ogden, " you will not be able to participate in the next class. Now that you know how to defend yourselves, we get to start having a little fun."

His students looked between each other. Professor Potter's dueling classes were known across the school as the best time in Hogwarts outside of a broom cupboard.

With that, the bell rang. The Ravenclaws clambered over everyone to hurry to Potions while the Gryffindors meandered on to Charms. Before he left, though, young Mr. Finnegan shouted a question: "and if we aren't hexing anyone in the, uh, hallways, sir?"

Harry's green eyes twinkled. There was always one. "Then I might say I've always found the Quidditch Pitch a good place for some sporting practice, James. Off you go now!"

And with that, Professor Potter's class ended. He spelled the lights down and retreated to his office. As he walked to the back of the room he gave a passing half-smile to the ceiling, where overhead the skeleton of Ol' Bessie swayed, animated by the errant magic of her charges and the school itself. Creatures closed in their charmed cages extended tentacles and wagging tails to him as he passed. His pet boggart, locked in a closet with the Mirror of Erised for company, knocked on Harry's magic as one might nudge an old friend's shoulder.

But Harry walked on past the collected displays of his youth and career. The serpentine handle of his office opened with a softly spoken word.

Super-charged air stung Harry's skin with the power of lingering magic and the scent of burnt leather struck his nostrils. His wand leapt out, a barely visible and un-pulsing luminescence immediately spread over him, hairs above his robes. A glance at the Auror magigears on his shelf confirmed the level of danger Harry was about to face.

He approached the crackling flames of his chair. A small red glow burned the dragon-skin, darkening it and cracking the hide as only few magical flames could. Over his shoulder and through the door, Ol' Bessie looked in and gave a bone-on-bone creak of exasperation.

"Well old friend," Harry said, bending down at his knees as he might with one of his students. "What ever are we to do with you?"