Harry found himself landing, in Snape's arms, on a lawn in front of a huge shed. Snape put him on the lawn, led him to a massive timber door and pronounced some unintelligible words. Snape opened the door cautiously, and peered inside.

"Oh," he exclaimed, closing the door.

"What is it?"

The Potions master seemed to ponder for a moment, then stared at Harry intently. "I want you to enter in complete silence, do you understand? And I am not going to turn on the lights. I want to show you something. Do you know the spell to see in the darkness? You don't? What has Flitwick been teaching you? Never mind." Snape shook his head, then flicked his wand in the direction of Harry's eyes. "Noctividens!"

Snape opened the door again and, silently, they entered. Dodging cauldrons, armchairs and other strange objects, Snape took him to a great portrait at the back wall of the laboratory.

In the portrait Godric Gryffindor and Salazar Sytherin shagged each other senseless on the floor of a medieval hall that could very well be at Hogwarts; Godric on top, from behind, ravishing Salazar, slamming him mercilessly against the rustic carpet. And Salazar thrust back in the same frenetic rhythm.

Surprised at first, Harry stayed completely still. Snape sat on an armchair facing the portrait and pulled the boy to his lap. Harry leaned on Snape's chest, with his eyes fixed on the portrait, as if hypnotised.

Finally, when the two Hogwarts Founders' rhythm seemed on the verge of tearing down the hall walls, both climaxed almost at the same time. Apparently drained, they lay on the carpet, in each other's arms, and fell asleep, not noticing that they had been observed during their entire amorous act.

"It's so beautiful... I'd never seen two men making love before," commented Harry, letting out his breath in a slow, shaky sigh.

Snape buried his nose in Harry's neck and hugged him strongly. "This portrait was in one of Hogwarts' corridors. One day Salazar asked me to take it from there and to put it in an isolated place, because, you know, they wanted to... And they couldn't do it in front of the students, who kept passing through the corridor all the time. Even at night, after the curfew, some insufferable, rebellious brats insist on walking through the corridors..."

"And some nasty teachers, who want to ambush the innocent little boys," countered Harry.

Tensing, Snape framed Harry's face and scowled at him. "Don't talk like that."

"I was only kidding."

"I know. But people might think... You know, I never touched any of my students... that way."

"Oh. That's not what I meant. I'm sorry."

Snape relaxed, and proceeded with his story. "So, after that, I brought the portrait here, and they seemed to find the arrangements quite satisfying... During the rare times when I am here and I come to the lab, however, they behave like perfect gentlemen."

"Because perfect gentlemen don't shag?" Harry didn't wait for Snape's reply. "You know, this portrait... inspired me: Gryffindor on top..."

"Ahem. I think I can indulge you... this time. But not here, in front of them. Let's go to the other end of the lab and conjure a four-poster bed, with curtains."