Okay, I sort of took some of OcUK's advice today, and imo it has not ended well.
This morning one kid was whipping me with a towel, and so I turned round and started to walk towards him, but he ran off. He's a year younger.
I saw him later on, he was walking up the stairs and I was walking down them. I gave him a punch, nothing hard, and said "don't whip me with a towel". He punched me back, very slightly harder. He was higher than me on the stairs and he kicked me in the head. It didn't hurt but I pretended that it did, so I started going semi crazy, punching him quite hard. But as I'm not that big it probably wouldn't have hurt him so much. Then I thought to myself "WTF am I doing" and just stopped. I kept telling him not to be such a dick. He told me to keep walking down the stairs, or he would 'hurt' me and push me down the stairs. I told him to apologise, and he said only if I apologise. I didn't at first, but then I did and so did he.
Clearly he walked away the winner
Honestly, I just don't have it in me to seriously harm anyone else, and because of my size I couldn't anyway.