Jim looked at the purple, almost spherical blob-like creature that stared back up at him with big, black eyes. It didn't have any other discernible features. If he remembered correctly from the information Spock had sent him about the planet, this was a good-natured animal that the natives held sacred. He kneeled down next to it and touched its skin, which was soft and almost velvety. The creature closed its eyes and... cooed? He tried petting it. Yes, it definitely cooed, and now it was leaning into his touch.
He stopped, and the creature opened its eyes again and stopped cooing. Then an appendage – which definitely hadn't been there before – somehow just stretched out from the side of the animal's body and reached for Jim's face. The creature stroked his cheek, and started cooing again.
Jim smiled in amusement. He had met a lot of weird animals, but he'd never been petted by one before. Another appendage stretched out from the creature, and another, and soon there were lots of purple tentacles, all trying to pet Jim in seemingly random places on his body, one of which happened to be his crotch.
"Whoa there, buddy." He tried to pry the tentacle away from that general area. "You're going for the heavy petting already? We've only known each other for like a minute; don't you think you should at least take me out to dinner first?"
As expected, the creature didn't answer him, but it wouldn't let him move the offending appendage either. It was much stronger than it seemed, and he wasn't able to budge the tentacle. And now, several of the other tentacles took an interest in that area as well, and a few of them started pulling on the hem of his pants.
Jim scrambled backwards, trying to get away from the creature, but one of the tentacles stretched further and wrapped around his waist, pulling him back.
"Spock!" He knew Spock was around there somewhere. "Spock, can you hear me? I need some help here!" He waited for a few moments as the creature continued fondling him. "Spock!"
There was a sound of rustling leaves, and Spock appeared. "Captain! Are you alright?" He hurried towards Jim.
"Yeah, I'm fine, but this animal here is starting to get a little too amorous... do you know how to get it off me?"
Spock approached them and grabbed the tentacle that was wrapped around Jim's waist, trying to pull it away, but several other tentacles coiled themselves around his wrists, and he was unable to move his hands. The moment he stopped struggling, the creature let go of him.
"I apologise, Captain, but it seems I am not able to pry the creature's appendages off you. Do you wish me to shoot it?"
Jim shook his head. "Nah... these are considered sacred, aren't they? And it's not actually harming me. Let's not risk a conflict unless it's absolutely necessary. Just... stay here, so that you can shoot it if it turns out to be dangerous after all."
Spock eyed the creature warily, but nodded his acquiescence. "Very well."
The creature had now managed to rip the hem of Jim's pants, and it pulled them down past his ass and started touching him through his boxers. Jim blushed as he continued his futile struggle to escape the purple tentacles. "I guess this thing really does know what it's doing; I thought it was just petting me randomly. I - oh!" He was cut short as a tentacle snaked its way in through the fly of his boxers and wrapped around his cock.
"Captain, are you certain you do not wish me to shoot the creature?"
Jim blushed furiously as he felt himself starting to get hard in the tentacle's grasp. "No, don't shoot. It's not hurting me." He let out an undignified groan as the tentacle squeezed his cock, and another one joined it inside his boxers to fondle his balls.
Spock flushed a pale green. "Very well. Let me know if you experience pain."
"Yeah, I will."
To his embarrassment, Jim was unable to keep himself from moaning as the creature kept pumping his cock and playing with his balls. Then the creature removed its appendages from his genitals and tore his boxers apart, pulled his pants completely off, and ripped his shirt from his body.
Jim closed his eyes, embarrassed by being splayed out naked like this, and by having been brought to hardness by some alien animal. His eyes flew open again in panic as the creature grabbed his thighs and spread them apart.
Another type of tentacle extended from the creature, this one slick and oily, and it probed between Jim's ass cheeks. Jim tensed up, clenching his ass even though he knew it was useless.
"No, don't shoot it. We want the natives on our side, remember?"
"I was about to say that I believe it will be more comfortable for you if you relax."
Jim blinked in surprise. He had never thought he would hear Spock say that when he was about to be fucked by an alien animal, but then he had never really expected to be fucked by an alien animal in the first place. But Spock did have a point, so Jim tried to relax.
Soon, the tentacle found his entrance, and it wormed its way inside. The creature started purring. The tentacle was maybe about half the thickness of a Human penis, and it slid in easily once it had gotten past the sphincter. It rubbed against Jim's prostate, and he moaned. He felt his blush return as he thought about the fact that he was being fucked by an animal in a forest in front of his First Officer. He looked over at Spock, whose skin was decidedly greener now as he looked at the place where the tentacle was thrusting into Jim's body. But Spock also had some impressive tenting going on in his pants. For some reason, Jim found that fact immensely satisfying, and it took away some of the embarrassment.
"Really, Spock? You're getting turned on by seeing me get molested by this thing?"
The Vulcan had the decency to look abashed. "It is a natural physiological response to witnessing sexual-"
"Yeah, yeah. Come over here."
The tentacle twisted inside Jim, making him moan again.
"I said come here. So I can give you a handjob. I don't want my First Officer to get blue balls."
Spock's eyes widened, and he stiffened. "I should stay here, ready to shoot the creature in case it harms you."
"Listen, I – nngh – I think it's pretty obvious by now that it's not trying to hurt me." Jim writhed on the ground as the tentacle kept stroking his prostate while wrapping another tentacle around his cock again.
Spock hesitated, but then he stepped closer. Jim reached for his fly, but a tentacle batted his hand away, tore Spock's pants and pulled them off before Spock had the time to react. He choked a sob as the tentacle pushed into his underwear, curled around his erection and started jerking him off.
"Fuck, Spock, that's hot."
Jim was a sweaty, moaning mess by now, and he pushed himself against the tentacle inside him every time it thrust into him. He kept watching Spock, whose control diminished by the second, and Jim couldn't decide if it would be more hot if the creature pulled down Spock's underwear so Jim could see his cock, or if he got to see Spock jizz in his boxers.
As if having read Jim's thoughts, the creature made a gurgling sound and ripped Spock's boxers off while maintaining its grip on his cock, and then it extended a third type of tentacle. This one was also oily, but much thinner than the one that was inside Jim. It stretched towards Spock's cock, and when Spock realised what it was about to do, he tried to pull away, but the tentacle already grasping him prevented him from doing so.
The thin appendage touched his cock, and then the tip inched its way towards his urethra and slipped inside. Spock groaned and closed his eyes.
Jim had never seen anything so hot in his entire life. He bucked and moaned, and as the creature twisted the tentacle that was inside him as well as the one on his cock, he went over the edge and spilled himself on his stomach. Moments later, the tentacle inside him stilled, and when it pulled out, he felt a warm, sticky substance running out of him.
He watched, transfixed, as the slim tentacle thrust in and out of Spock's cock and the other one jerked him off. Spock started moaning in abandon, and then the tentacle sped up, and he came all over Jim's chest.
The creature released Spock and made a few happy-sounding clicks and chirps, pulled all its tentacles back and became a blob again. It rolled off into some bushes, leaving Jim and Spock alone, sated, but blushing.
If Scotty thought there was something weird about having to beam down new uniforms, including underwear, to his Captain and First Officer in the middle of a forest, he didn't mention it over the communicator.