Bratty Sis (1998)

There is something about a young girl's coming of age where she can't control her bratty emotions and teenage sex drive. All she wants is sex; whether it's her step-dad, step-brother, step-sister, or even just to prove a point. She wants what she wants. And she wants it now. Don't let Mommy find out, unless she is the one instigating. Because with a Bratty sis in the house, anything can happen.