My sister, Tracy and me, Zak, are close, maybe too close nowadays. We were born 10 months apart, Trac being the elder. Homeschooled and closely monitored We always spent time together since we were young, on a small hobby farm, with Mom and Dad always nearby. Tracy has always had a great body since her early teens, with raven black hair, ample tits and a thin waist but ample ass. She grew quickly and into a beauty to behold: 5'5" almond Blue eyes, a slight rounded face, little nose and a pouty lips. We got older and the
'obvious' attraction grew for both of us, but neither of us could do anything about it but dream. WE were still both very innocent and would just blush at any sexual suggestion.
Our strict father dropped dead at work suddenly just after my 18th. He was 36. Our lovely 38 year old mother was devastated. She stopped caring at some point a few weeks later and tells us 'do whatever you want". More about my lovely mom, how she smiled again and how we saved the mortgage, as a family later. Our new freedom was strange. I graduated and was preparing for a boring summer. Then something changed our lives forever. A family with two college age teens moved in. A twin brother and sister who taught us all sorts of naughty things...
Now being free to wander in a smallish sized community we were excited to see the world. Tracy noticed our new twins, we'll call Rob and Jen, go riding on their mountain bikes for hours. We decided to play hide and seek and see what they did. It wasn't what we expected. The first time we followed them secretly to a storm drain where Jen would suck Rob and swallow all his cum. We managed to follow them a day later to an abandoned car where Jen lay spreadeagled on the hood while she was sucked to orgasm by a trained Rob. We both watched in fascination and awe. We looked at each other, blushed, said nothing and left.
The best spot, and action it seemed was close to home. Next morning I woke up to Tracy pushing me awake pointing to the twins leaving on foot, just as the sun was rising. I quickly dressed and followed them. They went to the old industrial zone and walked into a large building with alot of office rooms. We followed as they entered an office with a door and a bed it seemed. We found the next door office and slipped into the room. a pile of office junk blocked the door to the next office but we could, if hiding see all the action.