"Are you sure you're okay with this?" Asriel consulted his literal other half - Frisk, the human whose soul kept his lithe, white-furred frame together. Many years had passed, and while things had been strange at the start, the two had grown comfortable with their fusion. However, there were some subjects that were hard to bring up, even if they had both thought about them.

Asriel was lying in his bed, nude, staring uneasily at his currently softened penis. For a while now, he and Frisk had been developing urges, urges that had been hard to reconcile, but Frisk, ever-understanding, had been the one to ease Asriel into the act, to suggest the idea, and while Asriel had been uneasy at first, he had finally agreed - tonight, they would do this.

They would masturbate.

Asriel's heart was fluttering with nervousness, frozen in his half-bent position. He didn't know how to start - if he should start. What if he did it wrong? What if he embarrassed Frisk? But soon, a reassuring warmth crept up his body - a feeling, a 'Frisk feeling,' as he had come to know them: something like a ghostly embrace from his other half, that came whenever he was troubled. It settled like a weight, forcing him to shift into a slightly more comfortable position. "I just..." Asriel said, "I want to, but..."

Then, from inside himself, he could feel his heart fluttering again, but not from nervousness. "Oh..." he let out a light moan. This was a new sensation. "Frisk, what are you doing?" he asked, but his other half didn't answer. Instead of trying to reassure his soul companion that this was something he was okay with, he was taking the first crack at it. Frisk felt warmth that started at the base of his smooth, furred stomach, but quickly slid downward, causing his fur to stand on end as he experienced a new, soothing sensation.

Soon, his entire shaft was heating up.

Curling his toes and tensing his hands into fists, Asriel squirmed a little as the sensation continued to build. "F-Frisk," he grunted. His formerly soft penis was now slowly stiffening into an erection. He closed his eyes as he indulged in the warm throbbing coming from his penis, which was steadily growing inch by inch, each lengthening causing another jolt of pleasure to surge through him.

When Asriel opened his eyes, he realized he was staring down with his throbbing member, a hand unconsciously hanging just in front of it. He felt Frisk, an inquiring pang. He smiled a little, Frisk was asking him 'are you ready?' even when Asriel knew Frisk was eager for him to say yes. Luckily, he was more than ready, he was eager.

Taking hold, he gently stroked his shaft, the feeling of his downy fur tickling his sensitive flesh with careful ministrations took his breath away. But there was more to it than that, it wasn't just him stroking. Asriel's hips slowly gyrated as he and Frisk moved his hand up and down the shaft in unison, Asriel's breath growing heavier. He soon realized his other hand was tweaking the fur on his chest, Frisk's own emotion acting out on his body, soon softly massaging one of his nipples.

The sensual massage of both his crotch and chest would have been impossible for Asriel to maintain on his own, but with Frisk - with Frisk it was like the entangling of two lovers in a single body, and he knew this was close to the truth - Frisk was enjoying these feelings as much as he was, but it wasn't enough - not yet.

The two quickened their pace, this time led on by Asriel, who began to pump his shaft up and down. Asriel's other hand soon joined in too, cupping his small, quivering balls and teasing the head, causing small droplets of pre to dribble out, soon giving his white fur a slight, glistening sheen.

Asriel panted and groaned in pleasure, feet digging into his bed as he pressed his hips downward. He'd never felt anything like this before, their wills combined making him feel warmer, more aroused, more-

"Ah, Frisk, I'm gonna-" but the explosion of cum had already been born across Asriel's chest, and a moment after, panting and sweating, his head plopped down on his pillow, one hand on his still quivering, dribbling shaft. His mouth hung open, eyes staring up at the ceiling, unable to process anything but the pleasure he had just experienced.

"Frisk..." he gasped, "We've gotta do that again."

But his companion was well ahead of him. "H-hey!" Asriel said, "Don't put your finger in there!"

TO be CONTINUED? (Probably not)