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.
This lady knows how to have sex. I see she picked a stallion that's fit, and he's got a nice dick. Of course, lush-breasted already fucked, but all because she's appetizing, and her holes need a daily shake. A whore like that can't refuse a thing, so I'd give her a hard-on first to show her who's boss, and then I'd give her a mouthful. But the kid's young, he'll eventually learn how to put a lady like that in her place.
Chulan amor