You knew inviting your bully over was a bad idea, you thought maybe it could better your relationship with him. But instead it only made it worse, now you're standing there helpless seeing your mom turned into a slut for him.
Its not that you hated your BFF or wanted them to suffer - but your best friend's sister was so cute and well so was his GF - could you really pass up the chance with both of them? Maybe your best friend will never even know you used their sister and GF