Finally, with a look that caught me completely off guard with its genuine sincerity, she gave me a small nod.

The thrill of the anticipation almost ended the competition before it began. Would she really do it?

“Why have you stopped?” She asked, her snarky tone returning.

I grinned back wickedly and used my hand to encircle my cock again.

Casey leaned back onto her elbow and, keeping her eyes trained on me, let her hand drift down over her breasts and her stomach to her mound, starkly pronounced beneath her panties.

She cupped herself with her hand and looked up at me with a fire burning in her eyes, daring me to make a comment.

I held my tongue. I held my dick too, and gave it just the slightest jerk in the first salvo in this silent war with my sister.

I watched with complete fascination as she gave her pussy a squeeze through her panties. I could see her juices seeping out of the material to coat her fingers. I hadn’t realized how wet she really was. She was practically gushing.

Unlike her, I had had a little time to develop a margin of comfort with this insane situation. So I pressed my advantage by shuffling another half step closer to her and staring deep into her eyes while I tugged on my knob.

Her eyes narrowed, but she held my stare. In my peripheral vision, I caught her hand moving in slow circles over her sex.

I was between her legs, my cock aimed directly at her. If I unleashed now I would drench her fat, quivering tits and probably her face as well. She seemed oblivious to her danger though. She even resumed her taunting again.

“Does watching me touch my little pussy turn you on, big bro? Do you think you can come for your horny little sister?” I knew she was just talking like that to incite me, but it worked regardless. I felt a warmth in my chest growing as I pulled on myself and stared into her eyes.

Weirdly, I was beginning to realize, this was one of the most intimate things I had ever done with anyone. I had had sex that was less intimate, less intense and which caused less strange longings in my body. Performing this act with Casey was like the first hit of a new d**g. As it coursed through my bloodstream I knew that no matter what, from now on, I would forever crave it.

The more she talked the easier the words came to her and the more it seemed that she was beginning to believe them too.

“My pussy is so wet, Ed. Can you hear how juicy it sounds?” She increased her tempo so that I really could hear the squelch of her sopping cunt with each roll of her wrist.

“Don’t you just want to come all over my tits? I’ll let you. I think you want to give me your car, don’t you? Come for me, brother.”