If I were their teacher I'd force each one of them to stare at photos of STD's and aborted children for hours on end informing them that that is what they are going to end up with if they don't start showing some respect.
If I were their parents, I'd put them in a group where they help homeless people, send them to a program where they get to hang out in prison with sex offenders for a few days (carefully watched so there is no rape), send them to finishing school and a psychologist. After telling them they are horrible human beings who deserve absolutely no respect themselves.
Violence or sever punishment like detention or taking away their stuff will only leave them with resentment. You need to show them how fucked up they are becoming so you can knock some sense into them before it's too late.
