Based on episode 6. When Jin said he'd do anything, he meant 'anything'. This piques Mugen's interest, who is always eager to get one up on the usually unflappable roin. JxG, M voyeur.
This may be extended into a mutli-chapter fic if the demand is there. Please let me know if you'd like to see more.
I do not have any rights to the characters from Samurai Champloo, so please do not sue me for this shameless hack-job of fan fiction writing. I am sorry for the torture that you will soon suffer.
By George, I think he'd got it.
Jin felt ill. Sicker than he usually felt after witnessing Mugen and Fuu inhale enough food to feed a small village for a week. They had lost – his – swords. All for what – free food! They'd entered him into the Edo eating contest, fully aware that he ate less than most women. Definitely less than that Fuu with her unnatural appetite. They had done this against his will, using his precious blades to cover the entry fee. Mugen had all but passed out and Fuu had inadvertently thrown it in because of a fly! Jin wasn't mad, he felt… many things. Incomplete for starters and more than just a little bit worried.
Jin just stood there by the steps feeling lost, while Fuu moaned and Mugen sniggered
at his internal struggle. Suddenly, Jin's face snapped to the achingly familiar steel
strapped to a foreign set of broard shoulders. Ignoring the grating sound of Mugen's voice, Jin made his plea to the champion eater, causing the slightest flicker of distress to cross his eyes. Nothing. Desperation growing, Jin upped the anti.
"I'll do anything."
"Anything?"
Ignoring Fuu's muted gasp, with one final assessing look, Jin uncharacteristically threw all caution to the wind. Hiding his action from the others with his kimono sleeve and hakama, Jin placed his hand lightly on the champion's upper inner thigh while dropping his gaze.
"Anything."
Noticing the suddenly submissive samurai glancing up through his lashes and pressed far closer to the westerner than he'd ever seen Jin stand voluntarily before, and seeing the surprised but interested gaze trailing over his covered form, Mugen knew something was up. He was no fool or blushing virgin like Fuu. He'd seen that look many times before, and had given it on far too many occasions to recall. Absently realising that Fuu had gone and that the pair were walking away, Mugen decided to follow them. He'd never thought that Jin, who up until this point Mugen had assumed had not balls, or dick either come to think of it, would be affected by the loss of his blades so dramatically. Opportunities like this to find out anything about Jin didn't come about often, plus this would guarantee to be better than anything else he'd see today, except for a nice prostitute if he had the money. Shaking his head, Mugen realised with a start that he'd underestimated Jin. Big time.