The first hour of bedtime was rather uncomfortable for the merged duo, in more ways than one. Having become a German shepherd furry, it got rather warm for Nathan, tucked inside a sleeping bag while also sporting a fur coat. No longer able to sweat like a human, he found himself panting to cool off. It was quite the distracting experience, both being warm and the strange experience from cooling off this way. So distracting, he couldn't quite fall asleep.
And without the ability to fall asleep, his need to pee grew. And Jake could really feel it, on top of also being warm, which also made it difficult for him to sleep.
After a point, neither could take it any more. Nathan quickly pulled himself out of his sleeping bag, and started rushing to Jake's bathroom. "Sorry Jake, but I can't hold it! It's either the bathroom, or my sleeping bag!" Jake didn't argue. Though he hated the idea of being used to pee, the need to be used was way too strong.
Nathan used some muscles in Jake's penis-like body to coax Jake out of his sheath (neither knew those muscles existed until just now), and Nathan grabbed Jake between his fingers, aiming him down. For Jake, everything was happing faster than he could process. Being gripped by giant dog fingers, being forced to look down into a giant toilet bowl, the sudden flow of urine coming from somewhere behind him, and....
Honestly, it wasn't as bad an experience for Jake as he thought it'd be. He expected the experience to be like vomiting. But there was no coughing, no uncomfortable squeezing of his non-existant stomach. The urine comfortably flowed through his body and out his mouth. And at this point, it also felt very relieving. However, the taste was another matter. Even to his feline tongue, pee did not taste good to the phallic sphynx cat. He wanted to spit it out, but it kept flowing out of him, for a good ten seconds or so. Then came the dribble, and the jarring experience of Nathan giving him a light squeeze and shake to get the last remants of piss out of his body.
NOW Jake was able to start spitting. "Explain to me why this interests you, again?"
"Sorry. I just think the idea's neat, to be used in a way that would be unhealthy as a person. When you're a penis, piss is MEANT to come from your mouth. It's perfectly natural." Nathan continued under his breath a little. "Honestly, I kinda envy you."
Jake's feline ears picked up what he said. "Trust me, it's an acquired taste. Can you get me some mouthwash? It's under the sink, on the right side of the cabinet."
Nathan did as instructed, filling the mouthwash's cap with the minty liquid, and letting Jake have a sip (to the penis-sized feline, it was like sipping out of a bucket). After getting the taste out of his mouth, he spit into the toilet bowl, watching it splash way down in the urine-filled water, and the toilet was flushed.
Having no longer any reason to go to bed early, Nathan chose to stay up late. Jake, having gone through quite the exhausting experience, decided to pull back into Nathan's sheath, and get some sleep. The sooner he slept, the sooner morning will come, and he can be changed back to normal.