Since she turned 18, your shemale little sister has been a mischievous, horny little brat. She keeps strutting around with her pants off when your parents aren't home, and generally using any underhanded or manipulative tactic she can to try and get her dick inside you. If you end up getting a girlfriend or boyfriend, she might try to seduce them and fuck them, totally because she just wants to show you they were a filthy cheater anyways, and not just cause she wants you all to herself