I was my brother's younger sister by three years. As his only sibling, I guess I was nearest opportunity to improve his wrestling skills. Also, I was smaller. He would lie in wait for me. Then, he would spring out from hiding, tackle me and take me down. My struggles usually didn't work, but I could usually get him off of me by tickling him in the ribs.
I don't remember ever getting hurt, but I didn't enjoy this. I did become more observant of my surroundings as a result of his ambushes. I think as an adult I am more aware of dangerous situations than other people.
Is this desire to overpower part of boy-girl relations, I wonder? Once, a boy who was our next door neighbor pushed me down into a snow drift on our way to school (without any provocation on my part). I kicked him as hard as I could on his leg. His Mom called my Mom to complain about the bruise I left on him. I was required to take a different way to school after that. Several years later, this boy apologized to me for this incident and said he only pushed me down BECAUSE HE LIKED ME!