My brother came on my ass

So my older brother and I live separately. But when we went to a party at a mutual friend's house, he had a little too much to drink, so he asked me to spend the night at my place because he didn't want to come home drunk. I said sure, why not? We ended up at my place, chilling on the couch, talking. My brother started talking about how horny he was, and I was like, "Dude, I have a boyfriend, no way." But then he asked if he could masturbate while looking at me, and I was like, "Fuck it, why not? But no touching."

He likes it, he tells me to lie down face down, pull up my skirt. I'm wearing a pink lace thong, my ass is hanging out the side, barely. He stands behind me, starts pumping his cock. I want to see the show, so I pull my thong to the side, shake my ass. He loves it, he moans and groans, he comes.

I can feel his eyes on my asshole and fuck, I'm getting wet.

I could see he was getting closer so I looked deep into his eyes and said, "Cum on me, I want to feel it." I spread my ass giving him a clear view of my asshole. He lets out this fucking animalistic groan and then I feel his hot load splattering all over my ass, some even landing in my asshole, slowly dripping down to my pussy. Fuck, it was messy but it felt fucking good.

I cleaned up, gave him a pillow and a blanket and went to bed. I didn't fuck him, right? Just a little fun, nothing bad happened. My boyfriend doesn't need to know about this little incident. I didn't cheat on him or anything. Fuck, I need a cold shower.