We used to sit in my friend Stevie’s tree house and huff nitrous oxide out of a gas cracker we had stolen from Crate & Barrel at the mall. Stevie’s older brother bought the cartridges for us at the local head shop. They were silver and shaped like bullets. They looked the same as the CO2 cartridges we used to operate Stevie’s BB gun, which we also kept in the tree house. The tree house was where we kept everything we held dear that summer . . .