My younger sister "Kei" is a serious and caring, ordinary girl. One morning, after I overslept, she ended up helping me get dressed. At the time, I still had a morning erection, and Kei was startled upon noticing my hard cock. Despite her initial surprise, she quickly sensed my arousal. Taking advantage of her submissive nature, I let her touch my cock and savor the sensation. The subtle tension and unexpected eroticism of this situation heighten the story's appeal.