My father had remarried not all that long after my mother divorced him. We, me and my siblings, lived with my mother and he had moved quite far away with his new wife and her two kids, a little boy and a daughter two years my junior. We were all just little kids though.
We only visited my father once a year on account on how far he had moved away and all us kids got along just fine with each other. As fine as siblings in general are concerned at least and my little step sister was never much more than an annoying little girl to me.
That changed drastically one year. When we visited again it was like she had transformed into a different human being entirely. From hardly giving her a second glance before she suddenly caused a stirring in my loins. She was suddenly beautiful and she had tits to underline her pretty face which she never had before.
I was much more surprised when she woke me up with a blowjob the next morning.