Step Sister
After my first year away at college I returned home for the summer. My mother got married so I had a younger step sister. She was 15 tall, skinny and kind of awkward.
Well mom and her husband both worked 9-5 jobs. Step Dad paid me a few bucks to fix up paint their house. Well it didn't take long for two horny teenagers to start having sex all the time. I did enough to get some work done but for those three months I was home we fucked every day we could. By the end of the summer she would sneak into the basement and we would sleep together naked, then she would get back in her room before the parents got up.
Parents split up within a year but we remained in touch. Now we are both married with families. But occasionally we will meet for lunch to catch up, which means we are getting together for sex. No one suspects anything.
Hopefully the paint fumes covered up the smell of sex.