Viper heard a fluttering of wings behind him. He turned around and saw an imp flying overhead. The imp couldn't have been more than 3 and half foot tall but it was very clear that he needed to get a bigger loincloth as his current one failed to cover his enormous dick. Viper noticed something odd about the imp's dick though. It's skin tone didn't match with the rest of the imp. As he got closer Viper realised why. The imp had Viper's dick.
Viper began chasing after the imp and called out to him. The imp looked at Viper, smiled, and landed a few feet ahead of him. Viper caught up and asked the imp to return his dick.
"Not a chance," the imp said as he brushed aside his loincloth and lifted up his new cock to show it off. "This one is a massive improvement over my old one. But I'll tell you what. I wouldn't want anyone to go around dickless, so I'll give you my old one for now and if you can bring me a human with a better dick than yours or a demon with a better dick than mine we can sort out a trade."
Viper was unsure about the imp's proposal but didn't really get to think about it as the imp lunged forward, pulled down Viper's pants, and slapped his old cock into the space where Viper's used to be. Viper felt his strength return to him but felt odd having something so small between his legs when he was used to something much bigger.
"I'll give you 24 hours to find a suitable replacement for either my cock or yours. If you do I'll take the better cock if you bring me a human and then return yours to you. If you bring me a demon I'll give you their cock. If you bring me nothing I'm gonna leave things as they are and let my cock slowly corrupt you into a demon. Meanwhile if I keep your cock it's skin tone will soon become like mine whilst everything else will stay the same. Now tick tock, your time starts...now."
Viper had no choice but to start looking. He had to find a human with a better cock than his (a near impossible task) or else he'd end up being turned into a demon by the 2.5 inch cock in his pants. But if he can't find a human he'll find a demon because there is no way he's gonna be left stuck with this tiny thing forever.