If he could choose a memory, one single memory to be remembered for all eternity, it would be that second. That sublime, agonising second in which he realised all rationality was completely and utterly lost.
He would remember that summer breeze; the way it gently grazed his features, the pleasant coolness, the rich, sweet scents of roses it brought from nearby gardens. The same breeze which, during that exquisite second, caressed her impossible curls, making them dance as if they were alive, as If they had a mind of their own. The way she lifted up her head from the book she was avidly reading under her favourite tree and slowly, ever so slowly, closed her eyes in delightful pleasure. The simple, beautiful smile that made her lips curve in such tantalising candidness. How she leaned back on her delicate elbows, bare feet sensuously stroking the soft green grass. The blissful acceptance her big, bright brown eyes showed him when she finally opened them back and looked straight into his soul. His poor, damaged, cursed soul.
Yes. Yes. If Severus Snape could choose a memory, one single memory to be remembered for all eternity, it would definitely be that second.