"I love you." Mary snuggled deeper into Janet's neck, curled up on their bed. Janet smiled. "I love you more."
"No, I love you more." Mary poked Janet.
Janet nuzzled Mary. "Can't. I love you the most."
"Can't love more than infinity."
"Ask any love-ometer. My love for you is off the charts."
Mary hmmmmed. "I know how to resolve this." She jumped up.
"Hon? What are you—" Mary returned with a plastic-and-rubber skullcap wired to a briefcase-sized machine. "Is that—"
"My homemade EEG!" Janet looked wary. Mary moued. "Oh, come on. I'm a professional." She put it on Janet and hit the switch. Janet flinched, but the machine only projected a readout onto the wall. "Okay, love me."
Janet laughed. "You're so cute. Fine." The waves and spikes on the wall shifted.
"Okay, my turn!" Mary placed the cap on her own head. "Here it comes!" The waveform leapt upward, lines flattening as they hit maximum. "See? I love you more." She put it away and snuggled back into Janet's neck. Janet stared open eyed at the ceiling, eyes moving as her brain worked overtime, until Mary whispered. "Don't worry about it. I rigged it." Then they fell asleep.