Time to try out her mouth!

"So, Master... what say I put my mouth to a better use than the regular yelling at you and other Guild members?" Lucy purred from where she was sitting once the latest kiss had been broken.

Natsu gave her boobs another squeeze as he digested her offer. "You mean, give me a blowjob?" he asked.

"Yep!" Lucy chirped. "May I suck you off, Master?" she begged, clapping her hands together, and giving him puppy dog eyes.

Natsu chuckled. "You know what? Go ahead," he decided.

"Yay~! Thank you, Master~!" she cheered, floating off of his lap. She turned in the air, and lowered herself towards his crotch. He eagerly spread his legs a bit, letting his erection point upward, showing his eagerness to be pleasured, as well as how hard he was from her stimulation with her tail. She leaned in, and extended her tongue enthusiastically. "Unh," she moaned as her tongue slowly dragged from his base to his tip.

"You sure seem eager to do something that gives me pleasure, but you none," Natsu mused.

"Oh, but that's where you're wrong," Lucy giggled. "I am getting a lot of pleasure just by serving you... it's such a strong sense of compersion, that the word doesn't seem to cover it..."

"...com... compersion?" Natsu asked, trying the unfamiliar word.

"It's a sense of pleasure that one gets from others getting pleasure," Lucy giggled, fondling his testicles as she gave his cock another affectionate lick. "Even if it doesn't benefit the one feeling it directly. And as a Sex Genie, I have a profound sense of compersion towards my Master. My own pleasure is nice, but nothing compares to my desire to please you..." She then lowered her face, her mouth open to take his cock into her mouth.

"Oh, that makes sense..." he moaned as he tilted his head back. She easily took him to the root, as if she had done this her whole life. She hadn't, but this was trivial to her Sex Genie physiology. She began to slowly bob her head, withdrawing her head, and taking his cock back into her mouth, her tail undulating behind her. "Unh, that feels good..."

She giggled around his shaft, producing some rather pleasant vibrations through it. She certainly hoped it felt good, wouldn't be much point to sucking him off if it didn't. She slowly sped up as Natsu writhed under her skilled mouth, her tongue wriggling around his length within her mouth. He bucked his hips, unable to fully process the amount of pleasure he was feeling. This was all so new to him, and he was enjoying it thoroughly. Though not quite as much as Lucy was.

She gave his testicles a light squeeze as his cock started throbbing in her mouth. His sexual inexperience and her natural skill made getting him to orgasm a rather quick endeavor. He grunted loudly as he gripped the sheets of Lucy's bed, cumming right into her mouth. She swallowed it down eagerly like it was pure ambrosia. "Mmmm..." she moaned, until his member was spent. He was panting as she slowly pulled off of him, giving his tip a final, loving lick as she gazed up at him with doe eyes. "Yummy, Master... thank you for letting me please you..."

He continued to pant, but managed a grin at her. "I should be thanking you, honestly... that was amazing..." She giggled happily at his praise. It was so nice to hear her Master praising her like that!