Problems With the Pensieve
Snape didn't know what came over him. He didn't know why he wanted to do it. All he knew was that he needed to, he had to do it.
Walking down one of the long corridors with his flowing robes pulled tightly closed around his body, the sixteen year old Snape waited until he caught sight of Lily, walking along by herself.
He snuck up behind her and cleared his throat. "Um, excuse me... Lily, may I have a moment?"
Lily turned around and glared at him. "What Severus?" she snapped harshly.
He gripped the sides of his robes and pulled them open, revealing that he was completely naked under his robes.
Lily gasped.
"Surprise, Lily!" Snape cried before closing his robes and running off down the corridor before she had time to recover from her shock.
Twenty years later...
Harry Potter gasped, emerging from the Pensieve shivering and shaking, his eyes wide with horror.
"What is it Harry?" Ron asked with concern. "What's wrong?"
"Snape!" Harry said, his body trembling uncontrollably as he fought the urge to vomit. He had just been given Snape's memories before the Potions Master passed away from his injuries in the boathouse. "Snape, he...he flashed my mum! Severus Snape flashed my mum!"
Four months later...
Scabior sat in the cemetery beside the ghost of Severus Snape. It was a quiet peaceful afternoon when suddenly -
"Oh shit!" Snape exclaimed loudly, just now remembering that he had accidently included the incident where he had flashed Lily in the memories he'd given Harry.
Scabior gave Snape a confused look. "Wha? Wha's wrong?"
Snape hid his face in his hands, feeling thoroughly embarrassed.
"Don't ask..." he groaned. "You don't want to know..."