The brother shared his scheme on Imgur and the post has gone viral:
My sister is a lesbian and I’m gay but our parents are very conservative so she ‘dates’ my bf & I ‘date’ her gf, so if they stay over, they stay in opposite rooms, but jokes on my parents.
By "opposite rooms" I assume he means, guys in one room and gals in another. While the parents assume the son and his sister's "boyfriend" are chatting about dude stuff, like sports and girls. And the daughter and her brother's "girlfriend" are painting their nails and braiding each others' hair, before they all drift off into heterosexual sleep.
Hopefully in the future, homophobia and hate will finally die out and everyone will be free to love who they want to love regardless of gender and no one will have to lie to their parents. But until that happens, this is a brilliant ploy for glorious gay sex to happen under a homophobic roof.