A place designed for band kids to practice their instruments, practice rooms are hardly ever used for their intended purpose. More often, they are used to make out, have sex, go to sleep, or even just to hang out without the band director yelling at you. ALWAYS knock on the door before entering a practice room, especially if the lights are off.
When people are testing out there sexuality and give each other blow jobs in a music room. They will try and cover up there "actions" by saying that is a dare.