We present the case of a 16-year-old girl who was sexually assaulted with transanal forearm penetration resulting in rectal perforation. She required a sigmoid colostomy that was later reversed. The patient's history and physical examination was complicated by multiple factors: she was intoxicated at the time of presentation as well as during the assault; her presentation fluctuated over time, she was obese, and she carried a psychiatric diagnosis. This case report documents a rare injury caused by sexual assault in the adolescent population and also serves as a platform to discuss the evaluation and management of pediatric victims of sexual assault. We support a collaborative model of care including qualified sexual assault pediatricians, sexual assault nurse (or forensic) examiners, medical specialists, and the criminal justice system. The importance of developing updated sexual assault protocols, ensuring their implementation, and maintaining continuous quality assurance cannot be overemphasized.