Late one night on the Shera.
Yuffie had been woken up by what sounded like groans of pain in the room next to hers? She got out of bed to check it out. The airship was still in motion, but over the years, Yuffie's motion sickness had gotten better over time so she was able to move around the airship exceptionally fine.
She finally found the source of the noise. It was coming from where Vincent slept. Was he in pain? She opened the door quickly, busting in. She saw Vincent on his bed upright but a bit bent over, he sounded like he was having a hard time breathing. His back was turned away from the door.
"Vincent? What's the matter with you?" Yuffie started towards him.
"Yuffie," Vincent said in between heavy breaths. "You can't... be here right now..."
"Huh? What'dya mean? Something's wrong with you! What is it?" She asked stepping closer to him.
He raised his voice a bit more to try to scare her away. "If you don't go now I might do something I'll regret!"
But Yuffie didn't back down. She wasn't afraid of him. They had been through too much together. Despite his warnings, she went toward him further. She had barely touched his shoulder when, to her surprise, Vincent very quickly pinned Yuffie against the wall. He looked down at her, eyes dilated.
Yuffie looked up at him, a bit intimidated. "Vincent, what are you-?"
"I'm deeply sorry, but I need to do this. Forgive me. I'll only take a little, I promise." He said with urgency.
Yuffie had barely processed what had just happened within the last few seconds when she felt him lowering his head towards her neck, breathing heavily, uncontrollably, and sounding feral. He licked at her neck, which made Yuffie shiver. Then he sank his fangs into her flesh and started to suck her blood. Yuffie's eyes widened in shock. This sensation was foreign, different. It hurt but it also made something inside her feel hot.
She started to go limp. Her legs were about to give out. But before they could he lifted her up putting her legs around him.
"Vincent..." she sighed. "I, I feel...," she whispered, her breathing heavy. He said nothing, continuing to suck at her neck. "What...is this feeling...?" Yuffie moaned and then started to move her hips, grinding against his member through their clothes, her body getting excited.
Vincent groaned but then that feeling brought him back to reality and he reluctantly held Yuffie's hips still, making her stop. She whimpered. Things were getting out of hand. This whole thing was arousing her. If she continued grinding he wasn't sure he'd be able to stop. Her doing what she was doing was making him start to want more of the feeling that she was giving him.
Vincent quickly finished and let go of her. But doing that made her fall to the floor due to her legs still feeling weak. She held her hand to the wound now on her neck, staring up at him, face flushed. He regretted doing this to her. To his friend who always had his back.
