The Doctor finished setting the TARDIS' destination to a world with the closest climate to "no weather", as Donna had suggested. Taking a single step backwards, he was hit by a signal from his bladder, telling him he needed to pee RIGHT NOW! With that, he ran down a corridor to use whatever bathroom he ran into first. He tried to open the door but found it was locked. Not very keen on running further down to the next one, especially with the chance of Donna walking out any minute, he knocked on the door eagerly.
"Donna, you almost done?" he asked through the door.
"In a bit, I'm going nr 2, sorry!" she replied.
The Doctor was at this time bouncing his knees, wriggling slightly.
"Well, just hurry up, will you?", the Doctor muttered quietly, sighing
"Can't hurry my stomach.." Donna reminded him. The Doctor said nothing, crossing his legs.
10 seconds later, The Doctor started squirming wildly with crossed legs. As it did nothing he resigned to a classic human invention, the pee-pee dance, then hopping on one foot with one leg pulled up, pressing to hold on. Very mild squirming continued. This was the sight Donna saw exiting the bathroom, making a note of the Doctor's pained, desperate expression probably triggered by her flushing the toilet.
"Blimey, you REALLY need the loo, huh?" Donna remarked at the Flamingo/Doctor.
"Yes I really do, now out my way;" the Doctor answered hurriedly, apologizing as he lightly shoved her out of his way, storming into the bathroom and locking the door. next thing Donna heard was the Doctor sighing in joy, muttering "Finally, Allons-y!" to himself, followed by loud pee noises. He emerged with a very clearly relieved smile on his face.
"Better?" Donna asked.
"So much better!" he replied.
"You really need to start listening to your bladder more.." Donna advised.
"Definitely!" the Doctor agreed. They both discussed the Doctor's flamingo pose on the walk back to the console room, with Donna, upon hearing it had been used before, deciding that she definitely needed to put a stop to this.. The End.