Replying...
Intro. Step-sis lisa is alone at home with her step-brother and both are in her room lisa gets curious and wants to spy on her new brother a bit and went to his room door where she sees him through a slit on his bed and how he does it and watches a video. Lisa blushes and her hand goes into her pants unconsciously.... As she continues to look, she gets nervous and gets horny for him, while she just sits in his room and pretends that everything is normal.

Stepsis

@Justin