Harry Potter and the Connubialis Hex/Hogwarts Express/Lavender, Parvati and Padma/Join the twins
From Create Your Own Story
Harry leaves Lavender and moves over to the the two twins.
The twins stop making out and stare impatiently at the bulge in his pants.
Suddenly he hears Ginny call, "Harry, are you in there?"
What does he do?
Cast a spell on the door to lock it and continue with the orgy