You chose: Pocket the coin and change the subject to tax shelters.
image depicting a nervous human advisor holding a glowing coin while standing before a massive red dragon in a treasure filled volcanic chamber

Your fingers close around the cursed copper, its ominous inscription burning against your palm. With practiced nonchalance, you slip it into your money pouch where it clinks against mundane coins. 'Speaking of financial instruments, Your Scaled Excellency,' you say smoothly, 'have we discussed offshore volcanic tax shelters? The Obsidian Isles offer remarkable capital growth opportunities with dragon-friendly taxation policies.'

Valthorix's tail stops mid-sway. 'You mean to hide my gold... in other volcanoes?' The idea clearly intrigues him. A ruby the size of your head tumbles from his claw as he leans forward, sending ripples through the treasure sea. 'Elaborate.'

You unfurl a glowing parchment map across a clear patch of floor, careful not to step on any enchanted weaponry. 'These dormant calderas,' you point with your stylus, 'are legally classified as sovereign territory of no nation. Perfect for... asset repositioning.' The abacus's frantic clicking slows to a thoughtful rhythm as you detail how magma flows could conceal wealth from prying kingdoms.

Beneath your feet, the mountain gives another ominous shudder. The coin in your pouch suddenly grows ice-cold. Valthorix's nostrils flare as if catching a new scent, his gaze drifting to your money pouch. 'Interesting proposal,' he rumbles. 'But first - why does your petty cash smell of... forgotten oaths?'

What will you do next?