A few deep breaths and Severus began moving himself back to the frame of mind for having these lessons. He heard the knock at the door just as he was pulling the Pensieve down from the upper shelf. It would have to wait a moment as Severus wasn't about to keep a student waiting. Well, he amended, had the student been of the Hogwarts variety, he would have had no issue letting them stay there until Doomsday.
But for Theo, Severus wouldn't make him wait. He stalked to the door, robes swirling around his person as he opened it. There was the barest hint of a smile on his face, inclining his head to Theo in greeting. "By all means," Severus said, stepping aside, "do come in."
He turned, allowing Theo to let himself in as he went to the Pensieve. He said nothing as he removed the memories he had no desire to be discovered before taking Theo in. "It... has been quite some time since our last lesson. Have you been keeping up with your studies?"