The bond between my sister and I grew stronger by the day. We became very good friends and needless to say became better lovers. The more time we spent with each other socially the more we ended up loving and adoring and caring for each other. Similarly, the more time we spent with each other exploring our sexualities the better lovers we became for each other. As a matter of fact we turned each other on so much that we could hardly keep our hands, mouths and other naughty parts of our bodies from each other. At first I thought it was the taboo novelty of fucking my gorgeous sister in the office would wear out. My sister was afraid of that too. But after about two months of regular fucking and sucking each other and exploring each other's craziest sexual desires and fantasies we were convinced that we were going to be the life-time fuck partners. We reached a point where people at the office were convinced that we were dating exclusively.
Our sexual exploration continued on to the next level. It seemed like every few days we would end up trying something new. I discovered that having my sister on her knees behind me, spreading my legs, leaning me forward, having my large balls dangling between my legs where she can access them from behind, and having my puckered star-like ass hole exposed to her was the most vulnerable and the hottest feeling ever. I deeply enjoyed having my naughty sister tongue fuck my tight ass hole, and finger it and lick it while massaging my huge dangling balls with her tiny hands. She would try to wrap her tiny hands around my huge hanging cock and play with it and massage it while tongue fucking my ass hole. The best part was that she always knew when I was about to come. She would feel my balls get heavy and tighten up and my cock would start to pulsate and my asshole would tighten up around her finger or her tongue whichever one she would be assaulting me with at that time. As soon as she would get the indication that I was about to shoot my load she would wrap her sweet warm mouth around my cock, milk my balls and shove a finger up my ass hole far deep that I would shoot loads and loads of cum down her throat. I never saw even a drop leak out of her mouth. At one time she held some of my cum in her mouth and after I was done dumping cum she went back to tongue fucking my ass hole. Only this time she was pushing my hot cum inside my own ass hole with her sexy tongue and fingers. I was so dizzy with sex that I shot another load right there drenching her clothes that were laying on the floor in front of me all bunched up.
The next crazy thing that my sister and me got into was the result of us visiting a local costume shop to plan for our company Halloween party. We found more than we were looking for. For the Halloween party I was dressed as a doctor and she a nurse. Her amazingly large cleavage was showing very nicely through her deep v-neck nurses' outfit. Her short skirt was almost above her mid thigh and it was very easy for me to see her thongs when she would either bent over or stretch her hands up. A woman, Linda, colleague of ours from a totally different department also came in the nurses' outfit. Hers was the scrubs style but her cleavage was bigger and more visible than my sisters. This woman's 34DD's were very perky, erect and on display. We all had a laugh at the coincidence of these two women wearing similar outfits and we started talking. At one point my sister went to grab another round of drinks and accidentally called me "bro" which made Linda's ears perk up and eyes widened. She quickly whispered to me that she was under the impression that we were dating and I said, "yes, yes we are" and winked at her. She was a bit confused so she confirmed that this woman called me her brother and I said, "yes she did" and I winked again.
After a few seconds Linda had the biggest and the naughtiest grin on her face and the most wild desires in her eyes. When my sister returned I tried to give her a hint that we have been discovered. I was nervous not knowing what will happen next. I certainly did not want our secret to be disclosed in public so I was hoping that Linda's naughty smiles would lead to some sort of a secret-keeping deal. After failing attempts to hint to my sister of our discovery, Linda had started to put her moves on my sister and me. They were very subtle moves but let us know that she is comfortable being around her and that she likes us. She brushed her hands against my arms, touched Linda's shoulders and her waist, stretched herself so show her cleavage some more, asked us both if we can see her thongs from the scrub pants and so on. Finally, I saw Linda slowly slide her one hand around my sister's flat tummy press it gently and whispered something in her ears. A few seconds later I saw the most wicked smile on my sister's face and the naughtiest lip-biting action on Linda's. My sister grabbed my hand and said, "let's go doctor the operating room is ready." I followed Linda and my sister holding hands and hands around each other's waists right into the bathroom and we locked the door.
