An unexpected show

You stand in the doorway, hardly able to believe what you see. A girl sits atop the teacher's desk, her thighs spread wide and her head thrown back, her face slack with ecstasy. Another girl knees between her thighs, her head moving as she clearly pleasures the sitting girl with her mouth. Two others stand watching the performance, smugly arrogant smiles on both their faces.

You stare at the tableau, suddenly hearing the soft moans of the sitting girl and the liquid lapping sounds of tongue and lips on cunt. Your cock starts to harden at the sight, pressing against the fabric of your clothes.