“Why are you doing this?” I asked, a pleading tone entering my voice.

“I’m bored, remember? And making you suffer amuses me. And this is just too good. I mean who would have thought my dickhead brother has the hots for his little sister?”

“I don’t. I…” I tried to argue back, but it is hard to make a point when half your face is covered by your accuser’s pink underwear.

As I lifted my hand to remove the garment my sister tutted and waved a finger at me. She was still looking at her phone, but I stopped what I was doing.

“Wait, are you still recording me?!!”

“Yup, the first one was so good I decided to make a sequel. You had better start listening if you don’t want these to see wide release.”

In frustration I let my hand fall to try and cover my crotch and then I glared at her with as much venom as I could muster.

“Uh, uh uh.” She motioned to the hand. “Come one, big boy. Show me what you got.”

I knew my sister well enough to realize that she was not about to relent. Added to that was a certain kind of thrill I got each time she peeked over the top of her phone at my bare cock.

I mouthed the words “Fuck you” directly into the camera, but I capitulated nevertheless and wrapped my hand around my cock once more. It throbbed painfully.

I stood there for a long moment until my sister finally looked up into my eyes with an implicit challenge and mimed her hand jerking an imagined cock.

Slowly, and making sure she saw the protest in my eyes, I took a long pull on my hard dick.

Casey smirked in such a way that it made the dimple on her left cheek appear. It sent a warm tingle through me that I suppressed beneath a mask of anger.

“That’s it, Eddy boy. Beat that meat. Flog that dolphin,” As she spoke she moved into the room, keeping the camera trained on me. Not taking her eyes off me, she found the edge of the bed with one trailing hand and sat her generous rump down. She was close enough to me now that, if she leaned forward and stretched out, she could touch my cock.

Her camera was directed right at the head of my dick.

I maintained my look of stoic detachment while I slowly massaged my cock. It would not have been enough to get me stimulated under normal circumstances and, I figured, that if I did this for a while she would get bored and let me go. Whether she would let me get my hands on the video was another matter. But for some reason, the sheer wrongness of having my little sister watch me touch myself, completely naked, in broad daylight and in her bedroom was doing something strange to me. Already I could feel an intensely pleasurable buzzing sphere of energy just behind my dangling testicles which warned of an approaching climax.