How do they get out of this?!

The staff.

Suddenly, there was a bright flash of light as the main doors burst open, and a tall, skinny, British professor waltzed into the main room. His wand currently lit up with the Lumos spell as he saw the situation unfolding. Ginny was moaning and quivering on her knees at this point as Harry's hands desperately tried to cover her intimate parts, her mound slipping within his hand as she grew more and more aroused, her areolas rock hard and pointing through Harry's fingertips.

The others were standing in shock but with wands raised for another attack before the professor swishes behind him with a large blue pulse of energy, causing the others to retreat. Imperium Maximator! he shouted. The professor was dressed in large red robes like a vulture's wings and a rather odd pinstripe suit with what looked like red plimsoles - a style never before seen in Hogwarts, but the trio were **** for anyone decent at this stage rather than Snape or more Slytherin.

"Are you three alright? Your female friend seems a bit... preoccupied at the moment in time, and i think she needs some privacy." The professor said, shucking off his robes. "Wrap that girl up now in them, mess is completely fine.. as long as she's covered and comfortable." Harry Potter.. your reputation precedes you greatly.. as trouble seems to follow you and Mr Weasley like lost sheep! Ginny meanwhile was still writhing away to herself, the sight of this new professor only seemed to increase her movements as another stranger who was seeing her in this naked and sticky state. Her eyes rolled back as her feet started to curl on the floor, one hand had now retreated down to her soaking mound underneath Harry's hand as she moaned and groaned. "Ohh, mmm yesss" she squeaked and squelched.

The professor grabbed a nearby sheet from a box, "I think we need to look away gents.." he whispered.