There are probably several laws against this. In fact, Fred is almost sure of it. Something about incest. Or something. They're twins, so what, it's not like they can get each other pregnant. Neither can the other set of twins they're currently in bed with. They don't usually like women, too much effort, but Parvati and Padma, well...they get how it is. His twin will always be the most important person in his life, and vice versa. What's wrong with having a little fun?

Which is why George's lips are currently wrapped around his dick while he eats Padma out, and Padma's fingers are in her sister's cunt.

It's all just a little fun. And what no one else knows won't get them thrown in Azkaban.

Anyway, they only gave into their feelings (bad, bad feelings that they thought they would go to Hades for) because they saw Bill and Charlie getting it on in their bed. Probably because Mum and Dad would assume any noises coming from Fred and George's room were them experimenting. They used that to their advantage alot after Bill and Charlie moved out. Mum and Dad weren't getting any grandchildren out of them, but that's what they had Percy, Ron, and Ginny for. They'd get over it. Or maybe they'd get children out of them after all, the way the current situation was going.

You never know.