Or...

I walked to my sister’s mostly closed door, so focused on steeling my nerves for what I wanted, no; needed to ask, I didn’t hear anything.

We hadn’t had a serious conversation in a long time. And we had never broached talking about dating and, gulp, sex. I mean which eighteen-year-old brother talks to their older sister about sex and dating.

The door was cracked open as I raised my hand to knock, sweat was dripping down my forehead, my nerves encouraging me to run. Then I heard it. The soft rhythmic sounds of slurping and a man whispering encouragement finally filtered to my ears. I felt myself blush, I was sure I was red from head to toe.

I knew she and my mom were sluts but I had been locking myself in my room with headphones on to avoid them so much I hadn’t heard these sounds in a long time. I could recall the first time I had heard it. I was too young to know intuitively what it was.

Like today the door was cracked and I had naively opened it to find my then eighteen year old sister butt naked on the ground with a middle aged man plunging his small green cock in and out of her willing mouth. It had floored me so much I didn’t even realize the cock was green because he was wearing a condom. I honestly am not sure I knew what a condom was at that moment. Mainly I was shocked because the man was gross, I mean he had to be in his 30s, beer belly, patched hair on his body and bald and just ugly.

That sight had not turned me on. Now though, I was older and curious. I turned my phone camera on and snuck the top inch through the door, hitting record. I waited three whole minutes before I heard the man, my old bully I could tell, say in a muffled voice, “I’m cumming.”

I knew better this time, stopped the recording and tip-toed back to my room. I am only somewhat ashamed to admit I immediately jerked off while I watched the looped recording. Yay apps. My sister was fine, in a slutty way, and since she was on her knees on the ground only her partial profile was faintly visible as her hair hung covering most of her face, it was like jerking to a pornstar. Her ass and side-tits were amazing, though it appeared she had gained a tiny bit of weight from when she was 18.

I was glad to see she still made guys wear condoms, but was surprised she was dating a guy with a small dick, and surprised my bully was so small. I had heard girls loved big ones, or at least that is what porn told me.

I had seriously forgotten she now had a boyfriend, and who it was. I didn't want him getting pissed if I interrupted, or if I called his girlfriend a slut. I would have to wait to talk to her.

However, I didn’t hear them leave the room, and, maybe it was my imagination, I swore I could hear her moaning as I drifted to sleep.