"Doesn't look very magic to me," Luffy commented, gazing at the cock the stranger had just whipped out. The man claimed it was magic somehow, but it looked no different to any of the guys' dicks back on the Sunny.
"Oh but it is! If you get it to orgasm, it'll grant you a wish!" the man insisted.
"OOH really?!" Luffy demanded, "How do I do that?"
"If you just bent over and lowered your shorts..." the stranger instructed. Luffy started fiddling with his belt buckle hastily.
Bent over against a wall, the stranger slammed into Luffy's entrance repeatedly without any caution. Luffy moaned and grunted with every thrust. "O-O-oh gooooddd!" He panted, punctuated by each thrust. "Nnnggg!"
The stranger grunted along too, pounding Luffy as hard as he could. "It's good isn't it!"
"Oh god oh god it's so good oh my god!" Luffy babbled. The man smirked.
"Everything you'd ever wished for?"
"Ye-e-e-e-eeeees!" Luffy sobbed. With one final, long, hard thrust which sent Luffy's pelvis slamming into the wall, the stranger came hard and hot up Luffy's ass. He pulled out with a wet pop and zipped up his pants.
"Ahh...Thanks, and wish granted." He turned and strode away.
(It was hours later Zoro found Luffy slumped against the wall wearing nothing but his shirt, while his thighs were splattered with dried come and flecks of blood. He stared for a few moments and when Luffy didn't move, Zoro heaved a sigh and scooped up his captain, locating and pulling on his shorts for him, and carried him silently back to the ship.)