It takes three full hours to decontaminate my brother's bedroom. The walls, which I've always thought were orange, turn out to be bright red - the true colour hidden by the grime.
I go through six bowls of water and two bottles of washing up liquid. Each bowl ends up full of what resembles three-year-old dishwater.
At some point, Seb returns from his walk and goes into my room. When I've finished, I go to see what he's doing.
"Argh, Seb, get your shoes off my bedding! I'm going to have to rewash that now. And the floor! Where have you even been? And do you know how much washing you actually had in your room? it's going to take me days to get through that! Could you at least put it on the landing in future so that it doesn't disintegrate? Give me your shoes, I bet you've trampled mud all on the stairs. Don't go in your room until tonight, the carpet is still drying. Christ, it's like living in a pigsty!"
He hands over the mud-soaked shoes, telling me, "You sound like a parent."
"I am a parent in this house," I say as I leave and go downstairs. "You so owe me for this, Sebastian!"
I can hear him laughing, and he grins when I return to my room half an hour later with two plates of pizza. He then proceeds to eat three full slices of pizza in the time I eat one, which is extremely out of character for him.
"Do we have any more?" he asks with his mouth full.
I give him one of my slices. "This... makes a change," I comment.
"This is me repaying you," he informs me. "Don't expect me to eat any lunch at school on Monday, or for the entire week."
I sigh. "Dream on, my dear brother. Dream on."