Components? Now that was interesting, and he wondered if the happy memory required for casting a Patronus might qualify. But he was here to teach today, rather than pepper Magius with questions of his own. Therefore, he pushed down the urge to request more in-depth information regarding the components and carried on. "That is very similar to how our magic operates," Severus said, nodding once more. "There are certain wand movements required for certain spells, or adaptations thereof, and one progresses toward non-verbal spell-casting as one becomes more advanced." But neither were they here to compare notes, as much as he enjoyed conversing with Magius.
And he was getting sidetracked again, so he cleared his throat, and squared his shoulders. "The incantation for this spell, as you may recall, is Expecto Patronum." And luckily, there was no particular wand movement required, but since Magius didn't have a wand anyway, that point was rather moot. "There is a bit more to it, however, than merely saying the incantation. One must also concentrate on a happy memory as one casts the spell." Which wasn't always possible with Dementors about, but that was neither here nor there, at the moment. "The happier, the better. So, if you'd like to take a moment to choose a memory you would like to use, then we'll give it a try."