As a child, I had a very good (male) friend who was 3 years younger - we'd known each other ever since he was 1 or 2 as we lived in the same block for quite a while. We kept in touch after he moved out. We'd sleep over at each other's place now and then.
We hung out with our mums before a sleepover. He was 9, I was 12. After that we walked towards my block and he took my hand. I felt comfortable since I walked holding hands with my good female friends, too, he was a good friend as well, so it was the same for me ;-?. We got in front of our block and I said hello to a neighbour, also younger than me, who was playing outside. As he saw us he burst out into laughter and started the classic "X and Y sitting in a tree" thing, and I didn't understand why he was making such assumptions!!!