A month later

Shelby walked into the kitchen to see her brother feeding his face with another pop tart. She was dressed in a smart red blouse and black pants while her brother had on his lazy jeans and T-shirt.

"What are you doing? We're late!" she said.

"And that's my fault?" Greg asked. "I've been ready for 10 minutes and I've really gotta piss."

Shelby dropped to her knees instantly. "I forgot my glass, just pee in my mouth," she said. After a month of ingesting 2 liters of urine per day, she had lost any pretense of embarrassment at the act.

Donna Davis watched in amusement from the breakfast table as her high strong daughter encouraged her lazy brother to use her mouth as a urinal. She loved how the high-strung girl had adapted to being used as a toilet as a necessary evil in attaining the perfect body she always wanted.

Greg shrugged and unzipped. He preferred peeing in Shelby's mouth anyway, it shut her up for a once and just felt good to urinate into such a high-strung girl and have her drink all his piss down. He saved his morning pee now and could give her a quarter of her daily thirst for urine before she even got out the door. Nevertheless she held up her smartphone with the "Golden Eye" app which could accurately count urine volume as it passed by using the camera. Boys preferred it to peeing in cups, because who wouldn't rather piss in a girl's wide-open mouth?

Shelby held her mouth open as her brother started to pee directly in. The amber liquid filled her up then he dutifully stopped so she could swallow. It still tasted a little nasty but she could get it down without much trouble. The hot liquid even soothed her throat at times. She made herself swallow then opened her mouth and the hot stream of piss began again, making a loud splashing sound. It usually took four mouthfuls but today her brother gave her five full ones then a few halting shots of piss after that as he drained his bladder entirely.

"You could get more if you sucked the last drops out," Greg said hopefully.

"Don't be a pervert," Shelby said, standing up now and licking her lips clean of any urine that splashed out. Donna watched her children without comment, but slid her hand under the band of her leggings after they were out the door.