As the three of you argued, Wendy's strayed down to her (Olivia's?) dick. It was slowly stiffening in the breeze. She gingerly reached out to her new pleasure stick and peeled back the foreskin until the glans peeked out. She shivered slightly at how good the folds of skin had felt against the dickhead and began to rub the exposed tip with her free hand. She shuddered at the almost painful jolts of pleasure that surged through the penis and into her groin. She'd have to work up to this.
Wendy switched back to tugging the foreskin up and down the head. She used her free hand to massage her balls. She wondered a bit about her colossal ballsack; Olivia hadn't seemed to possess one. She guessed mermaid testicles must be internal organs, and the dick had adapted to her human anatomy.
Each jerk of Olivia's soft, cushiony foreskin took Wendy to new heights of bliss. She yanked the prepuce back and forth with all her might, sweating with both exertion and arousal. She finally felt ready to stimulate the head again. She took the hypersensitive organ and moaned happily as her nerves lit up with burning pleasure. The dick began to pulsate in her hand as the pleasure worked itself into a crescendo of delight.
Wendy screamed blissfully as her orgasm began. She collapsed on the grass as her entire dick (HER dick! Not THE dick, not OLIVIA'S dick. HER dick!) burned with the most intense pleasure she had ever known. The orgasmic fires spread into her groin, down her legs, and up her abdomen. An orgasmic haze clouded her brain; the world consisted only of Wendy and her orgasm.
"HOLY SHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIT!!!!!"Wendy gleefully screamed. She curled her toes as the first rope of cum (HER cum! SHE made it!) erupted from her dick. It shot over her head and splattered the tree behind her. The next sticky rope landed in Wendy's mouth, and she savored the exotic flavor of her cum. She'd tasted semen before, of course, but this was entirely different. There was a pleasant sweetness intermingling with the usual saltiness. Another wad of cum painted Wendy's chin and collarbone with a pearly white racing stripe. A final big load oozed into Wendy's bellybutton, turning it into a beautiful pearly lake. One last drop of glistening cum dribbled lazily out of Wendy's softening dick and into her pubes before the new organ flopped contentedly onto her belly, the spent glans withdrawing into the fleshy protection of her thick foreskin.
"F-fuck..." Wendy sighed once her orgasm had subsided enough for her to talk. She had honestly hoped that it would never end, that she would be completely consumed by total pleasure for eternity. Nothing else that her senses could perceive was worth tearing her mind away from that. She could see why Olivia was so distraught over losing this dick. Oh well... finders keepers. "That was... incredible! Just... fuck."
"You sure looked happy," you remarked.
Olivia crossed her arms sternly. "Are you quite done wasting my seed? That's the second load my dick's blown today, and I need to save some for babymaking with Michelle."
"That was the best orgasm I've ever had in my life!" Wendy exclaimed. "Sorry, honey, but it's true. And that was just from masturbation! Imagine what actual SEX would feel like!"