Take the high road and be the cool older brother. Smoke her out and teach her the ropes. Introduce her to interesting characters, and have her hooked up. Slowly, over time, have her try better, more intense drugs. Teach her the many methods for passing UAs and swabs. Make her the fun, loving party girl slut we all know. Once her grades start to slip, introduce her to meth, moly, and heroin. Send her down a destructive, downward spiral in which she may never escape. Laugh as she chases the dragon. That bitch deserves it. Sweet revenge.