Magius/Luke, Snape, Lily/Dave, Balthazar, others when they're around
That little elbowing maneuver very nearly made him ill. It was probably a good thing that Lily had paired him with Magius, in the end. He wasn't certain that he could entirely trust himself to duel Blake right now. Not that his dueling Lily was all that much better. Hopefully she wouldn't play the typical Gryffindor and get herself injured. She was a capable witch -- more than capable, actually -- but he still worried, all the same. He probably always would.
Severus took a deep breath, attempting to clear his mind of all emotion, which wasn't a trivial thing just now. But then he remembered that Occlumency, passive though it undoubtedly was, was another form of magic. He'd best stop that, because it could have unforeseen effects, one spells began flying. He would simply have to take deep breaths and hope for the best.
He cleared his throat when Magius approached, grateful for the distraction. "A combination of defenses, I think, has the fewest unknowns, as far as safety is concerned," he said, frowning slightly in thought. "I should hate to launch an attack without knowing whether your defense would work, at the outset." Even if it was something as simple as a stinging hex. Because he rather liked Magius, so far, and he didn't want to hurt him. Attack him, yes, but not hurt him, as odd as that sounded.