My older sister made me go down on her when I was around 10, she must have been like 16. When she was looking after me after school, we would pretend that I was puppy and she was my master. I remember specifically she used Strawberry popsicles, I loved strawberry popsicles. She would rub some on her hand, like "on accident" then told me to lick it off. Then she would rub some on her thighs and tell me to lick it off.
At some point, she ended up taking off her panties, hiking up her skirt, and thoroughly coating her box with Strawberry popsicle while I watched and pretended to be a puppy, barking and stuff. Then she just lay back and let me go to work, lol.
I think it must have happened a couple times, but I didn't really realize anything about it until a couple years later... I guess I was around 15? When I realized that it wasn't the most normal childhood memory...
I was kinda worried about it, so I ended up bring it up to her again, and she was REALLY embaressed, but we were laughing about it like "omg, kids are so gross, lol."
But after that she started acting pretty slutty around me, rubbing herself up against me... but what put the whole situation over the top was when I came home from Soccer practice one day to find her waiting for me in the kitchen in a thong and tight red top, sucking nonchalantly on a Strawberry Popsicle...
Needless to say, we went through a lot of popsicles that evening ;)