This one I know was meant to come after a scene I had written about Severus and Albus having an insane argument and Snape getting kicked out.
I found him two weeks later huddled under the canopy of a tree in the French countryside. It was a clear night and a warm breeze was blowing through the field of high grass and that singular weeping willow that did not belong. Pushing aside the curtain of hanging branches, I saw him sitting against the tree's trunk. Despite the warm weather, he was soaked through and shivering.
If he noticed my intrusion, he ignored me until I layed a hand on his shoulder. He jerked away violently and glared at me before getting up to leave.
He froze, turned to face me, and was no doubt about to spit or curse his sarcasm. I continued before he could, "You're right."
I sat back against the trunk where Severus had been, it was both an invitation and an apology. Severus remained standing.
I pretended not to notice. "What are you doing here?"
He tilted his head mockingly at me and answered literally, "Drying off." His voice was as smooth as it always was when he was composed.
I looked pointedly up at the canopy of branches above us. Beyond the green of the tree, the clear sky was filled with the bright orange light of a late summer sunset. "It doesn't look like rain," I remarked, forcing innocence into my tone.
"Not in France, no."