I Don't Know Why I Did It.

I'm a 25 yr old straight guy and i love sex with women, but one night after a few drinks with my 24 yr old straight step brother he passed out on the couch. After a while he was mumbling in his sleep and i noticed he had a tent in his pants, and before i knew it i'd unbuttoned them and my head was bobbing up and down on his cock as i sucked him off. I kept going until he shot his cum into my mouth, then swallowed it, put his cock away and buttoned up his pants. He has never said anything about it, and as far as i know he has no idea that it happened.