My sister, an erotic manga artist, doesn't know anything about men's bodies, so she leaves it up to her assistants. However, all of those assistants are virgins! So she called me to her sister's apartment where she works, and she used my body as a reference! She started by forcing me to get an erection, saying, "I need this to draw a realistic erect penis!" She played with my penis, saying, "I want to see your face when you're giving me a blowjob!" and "I want to see your face when you're about to cum!" Finally, she said, "I want to see you fucking me!" and ended up having sex with all of her assistants!