Alvida offers her ass.

"So then Master... You going to be fair and fuck my ass too, or are you done?" Alvida asked, getting on all fours slowly, and waving her butt at him.

Luffy smirked. "Yeah, definitely taking your ass," he said, scooting back over to her. He placed a hand on her shapely rear, giving a light squeeze, and she moaned and smiled at him.

"Go ahead then. It's all yours," she cooed to him.

He was all too happy to oblige and pressed into her rectum. There was almost no resistance despite the tightness of the hole, but that could be chalked up to her Devil Fruit. He was almost immediately all the way in.

"The Slip-Slip Fruit has a lot of potential regarding perversion with the powers," Alvida moaned as Luffy immediately started fucking her ass from behind. "I'm glad I get to show you Master..." she added, her upper body lowering to the sheets so she could cross her arms.

Luffy simply grinned and upped his speed, gripping her waist as he enjoyed her tight, slick hole. "Good girl," he moaned, enjoying every thrust immensely. She blushed a bit, but had a dreamy smile at his praise.

She began to pump her own hips back against him in time with his thrusts as she clenched her fists, and he went even faster, their flesh smacking together. Vivi repositioned herself slightly to get a better look at her new Master and sister **** going at it.

Sadly, something this amazing simply couldn't last forever, and Luffy soon started pounding Alvida's ass as hard as he could, and she gasped as her release quickly approached. "Yes Master, please, make me cum!" she begged, and he obliged by keeping it up, until finally, the floodgates opened, and just as she came, his seed gushed into her anus.

After coming down from her orgasm, she wheezed and looked back at him again as he slid out of her.