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.
Her stretching is enviable, as she also enjoys it. I have not seen such a pose before, and the guy was not watching, and diligently did cunny. After that, in gratitude she gave a deep blowjob and practiced anal.