Josh, a 12 year old trainer, had many Pokemon that he took care of. And while all the others, including Josh and his family, were asleep, an Eevee was wide awake.
He sighed, looking at the Pikachu laying on the floor at the end of Josh's bed. Eevee padded toward him, prodding him in the side in an attempt to wake him up, which was successful.
After Pikachu woke up, he gave Eevee a questioning expression, and he decided to just get to it. "I'm horny." He mumbled, to which Pikachu opened his eyes a bit wider, nodding and crawling closer to the other male. They had done this a few times before, but never got to finish due to almost being caught. This time, Eevee knew they were going to. Pikachu lowered his head between Eevee's legs, opening his mouth and drawing his tongue over his member in a long lick, earning a slight moan from the fox-like Pokemon. Pikachu continued, soon taking the tip of it into his mouth and beginning to bob his head, getting more moans from Eevee, who put a paw on his head to push him further. He started to move his hips, thrusting into the other male's mouth. It wasn't long before Eevee came, shuddering with pleasure. "MMmmmmpph!~" He let out a slightly stifled moan, trying not to wake up his trainer as he let the last remaining drips of cum drop into Pikachu's mouth, then pulled out, both of them panting a bit.
After a few seconds of the two panting, Pikachu turned around and raised his lower side, presenting his ass to Eevee. The evolution Pokemon padded closer, lifting his paws and resting them to the sides of Pikachu's tail and pressing the tip of his member against his tail-hole, making him twitch. He waited a few moments, before pushing into him, then pausing about two inches in, waiting for Pikachu to adjust. "..Alright, you can put the rest in." He groaned, still in slight pain, but sure that pleasure would soon overtake it. Eevee nodded, pushing the other 4 inches inside, sighing in pleasure. Pikachu winced a bit, but once again tried to push away the pain. He nodded, signaling for Eevee to begin moving, which he did. Slowly, he pulled out, then gently pushed back, starting to earn moans from the other male, who had started to move his hips back to try and get more inside of him.
Eevee kept thrusting, picking up speed as both of them started moaning, no longer worried about Josh waking up and catching them. They were in bliss, with this being their first time. Eevee began thrusting at a rapid speed, his and Pikachu's balls slapped together with each thrust forward. Then, Pikachu's sensitive spot was hit, which earned Eevee a loud moan. "Eevee! R-Right there!~" Pikachu begged, and Eevee obliged, aiming for the same spot, every time getting a pleasure filled moan. This continued for a good 7 minutes, and at this point they were both at their limit. "P-Pika-chu!~ I'm going to c-cum!~" Eevee shouted, which surprisingly had still not woken up Josh. "Me- AAAH!~" Pikachu couldn't finish talking before Eevee released inside him, causing him to follow after.
They both stayed like that for a few minutes, their hips connected and Eevee's member still buried in Pikachu's tail-hole. It seemed like forever when he finally pulled out, a bit of cum dripping onto the carpet beneath them. "That... was.. amazing..~" Pikachu breathed out, splayed out across the ground, almost asleep. Eevee curled up next to his new lover, nodding in agreement and nuzzling him.
They fell asleep, the sun starting to rise outside the window, and their trainer woke up to see his two beloved Pikachu and Eevee sleeping next to each other, covered in a substance unknown to his currently innocent mind.