Peel the banana and accept the challenge.
From Create Your Own Story
You open your mouth and bring the banana close to your lips. You glance at the merchant for a moment to confirm his claim. "You'd just let me eat your produce, provided I do it in one bite?"
"By all means," he says, "eat away."
You're confident you can fit it in your mouth, it's nowhere near the size of centaur dicks, and you've had plenty of time to exercise your throat. It slides easily halfway, but you slow for a moment and feel a slight gag. You realize, unfortunately, that your time in the woods was fueled by magic potions and minotaur milk. Away from such wild enchantments, you're on your own.
You close your eyes and breathe through your nose as you fit the banana deeper, widening your throat to make it fit. Drool slips from your lips as you ever so slowly reach the last third. Despite your endurance as a paladin your eyes water slightly and your legs buckle. You kneel on the ground and tilt your head up, determined to see if such a eccentric merchant was exactly what he said he was.
Your other hand, you notice, is holding you up by the groin, clutching your pussy as if it were a doll given to a girl for comfort. The throbbing pleasure you're giving yourself almost counteracts the choking pain of the banana, which is almost completely down your throat.