That the sister is interested in her foster brother's opinion is commendable. And assessing her worthiness from a man's point of view he can. But asking him to jerk off in front of her is kind of weird. He's going to get her, isn't he? Only this slutty girl is not scared at all - that's exactly what she wants. He ended up flushing a whole puddle on her tummy! Drove it.
I want dirty sex, I'll take a big dick in my mouth, I'll take deep down your throat, I'll give you in a tight asshole and will suck until you cum in my mouth