Her ass.

Luffy lined his cock up with her puckered rear entrance, and gripped her waist before pushing right into her. "Ah..." Hancock's eyes widened as she felt him enter her back door. "Oh yes Master... Take my ass..."

Luffy was happy to oblige and began to pump his hips into her. "Wow Hancock... This ass is so tight..."

"Oh... Thank you Master..." Hancock cooed, pressing back against him. "I'm glad it wraps your cock so snugly... It means it's fit to please you..."

Luffy sniggered and continued to pump his hips and pulled Hancock against him. She crooned, and resumed licking the mermaid. "Yes, ah, that's the spot..." Camie moaned, clutching the edge of the bath.

Hancock obliged, pumping her hips back against Luffy, who smirked and stretched one hand over to Camie and groped one of her boobs. The other hand went under Hancock and played with one of her tits. "Mmmph!" Hancock moaned into Camie's cunt.

Luffy began to pound into Hancock as Camie writhed under his groping and Hancock's tongue. "Good girls," he told them through his pleasured grunts.

"Ah, thank you Master," Camie gasped, her tongue lolling out. Hancock simply gave a pleasured mumble as Luffy felt his cock pulse.

"Here it cums!" he grunted out, before releasing his seed into Hancock's ass. Hancock and Camie screamed as they spasmed with their own orgasms. Hancock collapsed forward, and slid into the water. Bubbles came up as Luffy sighed, though amused and waited for her to come up... Before remembering she was a Devil Fruit user, and was now fully submerged, and thus couldn't even manage to push herself out of waist deep water at that point, especially when coming down from an orgasm.

One hasty moment of reaching in and pulling her out later, she was sputtering a bit, but smiling. "Sorry Master..."

"No problem," he chuckled.