I think it's incredibly hilarious that you're playing hentai games with your brother. That's just so strange haha
Usually people hide their pervy side from their siblings.
Well, my brother is the one with a bunch of drives containing his 'Special Collection'. To be honest, most of the time he's the one playing and I'm the one watching and 'learning'.
In a sense, my brother's playing a real-life, real-time 'corrupt your sister' game...except he isn't making much progress.
He teaches me about the stuff that happens to Aika, about the stuff she goes through. I mostly zone him out and focus on figuring out the plot instead.
I have to say this game is a good one. And there's just one thing I don't like about it, the romance route. There's only one, that of Crow aka Aomine ripoff (a decent one, but still). I wanted to explore other options. I wanted to try my hand with Hakuto and Lety. And most of all, I actually really wanted an exclusive Orizuru route.
Excluding Aika, Orizuru best girl hands down and dicks back in pants. (Looking back, my brother did make some progress in corrupting me after all...)
None of that was available from the few times my brother played.