Severus was aware of what the students were saying about him and about Faustus. They always believed that the teachers were oblivious to their gossiping and forgot that the portraits and the ghosts were all too willing to report what was going on. He was also aware that Faustus had overheard some, but not all, of what had been said. He would have spared his son that if he could because none of it was pleasant hearing.
Admittedly some of it skated very close to being the truth but some was nothing short of scurrilous. He knew who had said what however and some subtle punishments were being handed out, mostly in the classroom. Some students suddenly found themselves in almost endless detentions and Severus had made sure that the cauldrons were exceptionally unpleasant and filthy just for them. Even the Gryffindors would eventually work out what was going on. The few Ravenclaws who had been subjected to this had already done so and and apologised and therefore were no longer suffering through detention.
"Detentions provide salutory lessons in maintaining appropriate behaviour," he said with arch amusement. "For anyone."
Though given all he had experienced and seen, he doubted he could be easily caught in a prank. Even the Weasley twins had not been able to catch him though they had come close once or twice.
"Be careful pranking the Slytherins," he said mildly. "They tend to bite back." That was all the warning he would give. His serpents could be fiendishly inventive at times and he had no objection to them retaliating. Within reason, of course.