I guess the brother is always the last to know, so sorry to have to tell you this buddy, but your sister is the best cocksucker in town! And It's not just me saying that, you can ask any guy around... because she's probably sucked his dick and drained his balls of every gushing drop of cum he had. So don't look too closely at the phone numbers written on walls of public bathrooms everywhere, you might see one number you'll recognize!