You look to the fairy, who still has that impossibly smug grin on her face, and sigh. You then ask her nicely to change you back. You are surprised because it comes out as actual human speech, perfectly understandable. But the fairy doesn't look any more amiable. She just smiles mockingly and you know things won't get any easier for you. You strive to be polite once again, saying that you shouldn't have gotten angry so easily or so fast, that her powers are most impressive and that you'd be VERY grateful if ever you could retrieve your original human form. The fairy asks you why you cannot simply be happy as a unicorn, which are the purest, gentlest and most admired animals in creation and you politely say that even though it might be the case for human females especially, it ids not the the case for you, because you just one your gender and human body back.
"Why?" says the fairy. "Being a mortal, especially a male, must be awful. Being a fay is so much better! More liberating! And not only is so freeing, it can last a very, very long time! Much longer than human lives, at any rate!"
You sigh deeply.
"Look, I appreciate the offer, but no. I like my human life, for all its inconveniences. Sure, I need to worry about my job, rent, money, always money, my future long-term plans but I don't want to be a fay creature or female. I want to go back to my world. I'm sorry to have offended you, I really am, but I just want my human life back."
The fairy gets deep in thought thanks to your word.
"Mortals," she sighs in turn.
She looks straight at you a bit more than continues.
"All right. I understand you calling me a 'firefly' was not the insult I thought it was. And I admit I was a bit harsh. So I'll help you."
"Really?" you say with hope in your eyes.
"Yes, really," she smiles dusting you with her golden powder once again.
And it works! You can already feel you body changing.
"It's just that sometimes, you humans need help in spite of your dim selves!"