Jeff took a moment to adjust; He was bloated, with pee up his nose, but the taste wasn't bad. "I could actually go for some more..." Jeff felt weirded out, considering this was his sister's pee, but at the same time... he didn't mind it.
He could still feel the bits that he missed before soaking into the diaper behind him, as he thought about what caused it. His attempt to move. "Hmmm..."
He tried to move again, but this time only moved his lower half, which was aligned with her vagina. This stimulated her again, putting pressure on her bladder.
He could hear that it was coming this time, so he closed his eyes, plugged his nose, and opened his mouth. As he adjusted his face to get as much of it in his mouth as possible, another torrent came out. His mouth was flooded, with the pee going down his throat.
This one felt longer; Jeff was more bloated, with more and more pee building up. After a few minutes, it felt like he was going to burst, but he kept drinking it.
Diana could somewhat feel it being let out, and was confused on why she was peeing without feeling wet. She snuck out to the bathroom as Jeff continued drinking.
She completely forgot Jeff was there, and sat down on the toilet, pulling her underwear down. She pushed it out harder, thinking she's letting it out in the toilet.
She sat there for several minutes, pushing out pee. "I knew drinking all that water was a mistake..." Jeff kept drinking it all, with at least a gallon of pee added to the previous burst.
She finally ran out of the flow, Jeff now completely full. He could still feel Diana pushing, however, and guessed she was doing both while she was here.
He felt her stop, before a piece of toilet paper wipes the area Jeff is in. "Thank god it's the soft brand..."
She finishes up, pulling her underwear up over Jeff once more. He could've sworn the diaper was smaller, but ignored it...