Di lifted her head from the hollow of my shoulder. Her breathing had become quiet and regular. The quickness of the movement pulled me back from the fuzzy zone halfway between sleep and wakefulness.
"What?" I whispered drowsily.
"Shh." she whispered urgently.
I listened. Over the hum of the AC fan, which provided a background of unnoticed white noise, I heard a rhythmic rubbing type of sound. It was so soft I would not have noticed it except for Di's sudden attention.
"What is that?" I mouthed at Di. We were both a bit paranoid after having almost been caught earlier in the evening with our shorts down, literally, by our mother. We had just finished watching each other masturbate when Mom had knocked on my door and asked to come in. We thought we were busted. Instead, she said good night and was on her way without disturbing us further. Reprieve. Di should have gone to her room. She didn't. She stayed. We should have ended it there. We didn't. She was still naked. I was still naked. I liked looking at her. She didn't just want to watch. She wanted to touch my cock. Our 'looking only' rapidly evolved into 'touching, sucking and licking'. That's why we were drifting off to sleep. Another orgasm and we were tuckered out. I thought she had fallen asleep. I was nearly asleep.
Di's brow furrowed in concentration as she listened to the rhythmic sound that seemed to be coming from the door.
Di got up and padded over to the door. I enjoyed watching her naked ass bump across the room. She leaned over and put her ear next to the door. I enjoyed that maneuver too. Bending over is an under-rated maneuver, especially when executed by my naked sister. "My god she looks good," I thought to myself while admiring her boobs as they shifted and hung from her chest. The dependent appendages begged to be cupped in my palms. Fuck that, I wanted to lie underneath her and take them in my mouth. I imagined how her nipples would feel, how they would tighten, how they would lengthen and become hard under the caress of my tongue.
She looked at me and waved me over.
Her boobs swayed tantalizingly with the beckoning motion of her arm. My mouth watered as the nipples traced twin arcs below her chest.
"What the fuck is that?" she mouthed. She seemed paranoid now. I could tell she was worried it might be our mother. Mom almost catching us together had scared the bejesus out of us.
"It can't be Mom," I whispered. "She went to bed. Didn't she?"
"What is it?" Di asked again worriedly.
I put my palm against the door. I felt a rhythmic vibration that matched the cadence of the almost imperceptible sound. The sound seemed to be coming from the door itself.
I gently pushed Di to the side, quietly turned the knob and slowly pulled the door open.
"Jesus," I blurted and jumped back in alarm"
"Ohhh," squealed Di as she stumbled backwards equally alarmed.
We had both reflexively recoiled away from the movement of a dark shadow beside the door.
"Christ," I said in shock.
"Mom?" Di blurted in surprise.
Time seemed to slow down as I took in and processed the surreal scene. Mom was sitting on the floor leaning against the doorjamb. She was propped against a couple of pillows and slouched comfortably with her head resting against the wall. My eyes were drawn by the luminous quality of her naked breasts. Their untanned whiteness stood in stark contrast to the dark tan lines below her breasts, the dark fabric of her top that was bunched loosely above her breasts, and the dark tan of her upper arms that trapped and pressed the large white globes up off her chest. Her large dark nipples floated like islands as her white boobs jiggled in response to the movement of her arms.
"Wow, she's limber," popped immediately and inappropriately into my head. Her knees were bent and so widely splayed that their lateral aspects rested against floor. The soles of her feet touched like praying palms pressed together. Her heals rested on the floor only inches from her crotch. "Really limber," I thought again. Dark skimpy panties were draped around her ankles. Both of her hands were busy in the obscenely exposed area between her legs. "Nicely trimmed bush," I thought even more inappropriately.
Di looked at me. I looked a Di. I think it dawned on us at the exact same moment. As ludicrous as it seemed and as ludicrous as it was, we both realized at the same instant what the mystifying sound was. The sound had emanated from the rhythmic movement of Mom's head against the doorjamb. The rhythmic movement of her hands had caused the rhythmic movement of Mom's head. Her hands and fingers had been busy brushing the beaver, flicking the bean, getting lost in the deep end, perfuming the fingers, roughing the muff, spanking the kitty, SHE HAD BEEN MASTURBATING!
