seriously... that might be his biological sister...

I agree with Emily, sex with family members shouldn't be taboo. And in my opinion, it should be encouraged over sex with random people or anyone not related to you. You are much less likely to get judged by family, along with the fact that they would have that familial love to it. And it's much, much better to learn about sex from family, especially at a younger age.

sex with family shouldn't be taboo. i've done it & it's the best sex i've ever had. no man can fuck me like dad fucks me, & no girl is a better fuck than my little sister. sex with mom was super special, & my uncles are just rlly fun to fuck. grampa had the biggest dick of all of them, & knew how to use it. grandma was an excellent teacher & taught me how to take gpas big cock & how to suck 1 that big. my cousins are fun fucks too, with lots of laughing orgasms, which are awesome!