Sirius
This has always been my tree.
I found it back in first year, in the very first week of term.
I'd met Prongs a few days earlier, on the train. Not that he was Prongs then. Just James.
Every day those first few weeks, as soon as class let out for the day, I'd drag him out to explore the castle. Wormtail would always trail along after us. Moony usually didn't - he'd beg off, pointing out that we had homework. I complain about his missing sense of fun now, but honestly it's come a long way from where it started, all those years ago.
We'd just had our very first Herbology lesson. I guess it must have been the second day of the term. Classes were out for the day, and we were already outside, so I decided we'd explore the grounds that afternoon. Even Moony came along - I guess even he couldn't resist the good weather. And besides, it was Friday.
At that point, I'd really only seen the lake from the boats the first night. It'd been dark then and hard to get a proper view, so I was pretty excited to get a better look.
There's a beech tree by the shore - we took turns climbing it, seeing how high we could get. Moony didn't, of course. He was much too dignified for that. He just sat in the grass below, staring up at us.
After a while, we got bored of the tree. Wormtail joined him; Prongs and I waded out into the lake and tried to dunk each other. When Prongs succeeded, I declared all out war and started trying to splash all of them. The others darted away, but I got Moony. He sputtered, stepping back in shock. Before too long we were all soaking wet - shivering, but also laughing.
None of us knew any drying charms back then, so we all trooped up to Gryffindor tower together to change into dry clothes for dinner.
The next day, I got a Howler from my parents. How dare I rebel like this; they've never been so ashamed - all that crap. I guess someone had finally told them I'd been sorted into Gryffindor. I certainly hadn't.
Which left… Cissy.
Across the hall, I saw her smirking. Before I knew it, I was on my feet, striding towards the Slytherin table. I think I would have punched her.
I made it halfway there before Prongs grabbed my arm and steered me outside, Moony and Wormtail hovering behind anxiously.
Once we were safely outside he let go. I stalked towards the lake, on autopilot. Before I knew it, I was halfway up the tree, hidden from the world by its branches. The others stood uncertainly at the base for a minute, then Moony climbed up to sit beside me. Prongs and Wormtail stood guard below.
Ever since then, this has been my tree. When I'm upset, this is where my feet take me. Sometimes I go punch someone first, but I always end up here.
And Moony always comes after me. At some point the others stopped coming, but he's always been there.
Sometimes I vent; sometimes we just sit in silence until I feel ready to face the world again.
Somehow he always seems to know exactly what I need.