A Pretty Firm Rule
"So, this is my place." Robert spread his arms and turned a slow circle. "It's not much, but... it's not much." He smiled. Mallory took a few strides into the center of the space and pointed at a closed door. "Bathroom?" He nodded and she stepped through the door without hesitation, but didn't close it. Robert heard his shower curtain clatter. "Hey, you, uh, feel like taking a shower?" Sensing an opening, he tried to lean confidently in the doorway. She was peering into the open tub.
"Nope," she said. "I have a pretty firm rule about checking the tub for bodies." Nodding in satisfaction, she left the bathroom. Robert stepping to the side so she could pass.
"Okay, um, why would you have that rule?" Robert watched her make herself comfortable on the couch.
"Ever gone to the bathroom after sex and found a body in the guy's tub?" She cocked an eyebrow at him. Robert shook his head. "Well, once is enough, y'know?"
From then on, Robert was the sort of person who checked to make sure his date wasn't the sort of person who checked the tub for bodies. It didn't help him win many second dates.