"Nanay," breathed B as he thumped up the stairs, "I'm desperate."
I did my best to keep up behind him, anxious to learn what he meant by "desperate" and where he had learnt such a grown-up word.
"What does desperate mean, B?" I asked.
"It means," said B, opening the stairgates and rushing through the first door on the landing, "that I need to go to the loo."
And without a backward glance, he was shutting the bathroom door behind him, leaving his nanay silently giggling with mirth.