A big surprise

The alien's four hands caressed Aaron's body, seeking out any place that gave him pleasure. She squeezed the muscle at the juncture of his back and his legs firmly, tousled his hair, and ran fingers up both sides of his body. His male sexual appendage was performing wonderfully at stimulating their female receptacle. Their lower tendrils pushed out of their protective flesh and started fondling his penis and testes. A groan of pleasure from his mouth told them that he was enjoying the stimulation. The delicate tentacles on the hand that groped his backside found a very sensitive spot between the large muscles that they touched, judging by the way his body stiffened when they tickled it. Further touching found a tightly closed orifice. That must be the waste opening Aaron had mentioned earlier.

"What are you doing down ... Aaaaaaah!" Aaron said when he felt the tiny snakes at his asshole. The moan came when several of them penetrated into his anus. He'd never had anything in his butt, never crossing that subconscious barrier. He was going to protest further when the squirming mass found his prostate gland, and amazing nerve impulses spread out from it. He bore down and thrust harder into the extraterrestrial's cunt, his mind overwhelmed by ecstatic pleasure.

His increased response to their exploration of his rear orifice spurred them on to try something else: they pushed out their male sex organ, which conveniently appeared between his legs. It snaked around until it was poised at the new-found opening. Thick lubricant squirted from the tip, and the tendrils left a small gap in the muscular ring. Making their male organ about a half-inch thick, they pushed it forward into Aaron's hole.

Aaron howled at the intrusion, but his psyche was too revved up to object. The alien's cock was in his ass, and it felt like heaven. His pounding movements that pistoned his cock into their body also drove their cock into his ass. When the creature increased the width of the prick to a full inch and rapidly increased and decreased its length, effectively pumping it in and out, Aaron's nervous system couldn't handle it anymore and he screamed, unleashing a flood of sperm into the strange ambassador's sex cavity. They were whistling again, which Aaron knew meant they was very aroused. Never having experienced a prostate orgasm before, he was surprised by its intensity. He must have cum for a full minute.

Lashu didn't let up with their rear penetration when the human was done ejaculating. Every inward thrust brought a groan from his throat. In thirty seconds, the man started pounding into Lashu's sex again, his penis having never wilted. The rubbing of his prostate gave him continuous hardness, and he was over any fear of anal sex. It felt just too good to stop. The creature's whistling started to warble again, and Aaron sucked another triple nipple into his mouth. In another minute of hard double fucking, his cock spewed forth a new load of sperm, and the alien cock in his ass sprayed unearthly fluids into his body. The whistling hit a very low register at this point that Aaron had never heard before. Both human and alien bodies shook and quivered in their climax.

Aaron slumped on top of the alien ambassador, his cock finally softening and slipping from their sex. Lashu decided this was a good time to retract their male organ as well. They both just lay there for several minutes.