Sirius watched, obviously fascinated as Bellatrix slid the knife through Remus' shirt and over his skin, gaze flickering from the knife's movement to Remus' face, gauging his reaction. Torture was an art, he thought, and Bellatrix a gifted artist, and he wanted nothing more than to learn. And, of course, to apply that knowledge to a more practical sort of learning, but for the meantime he was happy to watch her progress.
He got a particular thrill from Remus begging, his voice enticingly breathless, because Remus never begged, and even after the worst of moons he insisted he was fine and tried not to let on just how much agony he was in, but this was different. It was a bit intoxicating, really. "Does it hurt?" he asked, almost innocently, gaze settling on Remus' face once more.