One thing you may not know about Sirius Black was that he was a good older brother, and good older brother that he was, he decided he needed to talk to his baby brother, Regulus, about girls. There was no way he's let his family with their "pure" ideals get to that boy first telling him to only be attracted to ladies because of their bloodline. That wouldn't do.
He saw his little brother, so much like himself in looks, walking down the hall. He reached out, grabbing the Slytherin and dragged him into the empty classroom he was occomping.
"WHAT THE HELL SIRIUS!" Regulus yelled, as Sirius lazily stood in front of the door, blocking the exit. Regulus looked pissed (and he was) for being kidnapped by his disgrace of a brother. Not that he himself thought that his brother was a disgrace.
"Let's chat." Sirius seemed a little nervous to the younger Black. He was. It wasn't every day you talked to your baby brother about girls like he was planning to.
Regulus raised his eyebrows and crossed his arms over his chest, relishing in the fact that Sirius was nervous. "Then chat."
"Look, I know Mother says otherwise, but if you see a hot girl it's fine to think she's hot no matter her blood-" Sirius's running-of-the-mouth was cut off.
"I don't like girls that way." Regulus said matter-of-factly. His voice didn't even have a hint of lies.
Could you believe it? A homosexual Black? Sirius was gob-smacked. "W-Well that's fine too, this could go for boys too…" Sirius was still shell-shocked.
"I don't like boys like that either." Still no trace of lies.
Sirius was very very confused. His head was tilted and on his face was the look of utter-confusion complete with squinty-eyes and fly-catching mouth. Whaaaat?
"Sirius, I'm asexual and I don't want a romantic partner of either gender." Regulus explained, gray eyes looking bored though he did find Sirius's face comical. Sirius didn't respond.
"Well, nice chat." Regulus shoved pass Sirius who appeared to be frozen.
After Regulus left for whatever class he had to attend or wherever hehad to be (you never know with that boy) Sirius spoke. "Regulus is one wired kid."
A/N: Weeeeeelllllll, the plausibility of Regulus's asexuality seemed to make much more sense at 1 in the morning. Also this is my first Harry Potter fanfiction in a long while. I hope you enjoyed though.