Hi :-) This is just a drabble that came to my mind when I read a story about Luna tricking Harry into having a harem and Hermione into joining it. Not that I mind that particular trope when it's funnily written. I just mean neutrally: that's where the drabble came from.
If you by accident found your way to this story and decide to try it, I hope you have fun :-) I certainly did :-p Harry Potter is not mine.
"So let me see if I got all of that right." Harry said. Hermione nodded and looked down nervously.
"You found out Ginny, Luna and a couple of other girls want to create a harem for me."
"Yes."
"Without asking me first?"
"Yes."
"And you tried to convince them not to but failed?"
"Yes."
"And now you think they are going to stun me and enact a harem ritual without my permission?"
"Yes."
"Hermione? Can I ask you a question?"
"Of course." Hermione agreed.
"Why do you think I don't want a harem?"
"Because you are much too noble to ever accept being with more than one girl at the same time, obviously. Otherwise I would have started a harem for you years ago."
"You would've what?"
"Naturally. I dreamed about becoming your harem slave since first year, didn't you know?"
"How was I supposed to know that?"
"I dropped all the usual hints."
"There are 'usual hints' for that kind of thing?" Harry asked in wonder.
"Of course there are. What did you think I wanted to tell you by riding on a Hippogriff with you to save your godfather?"
"That's a 'usual hint' for wanting to be a harem slave?"
"Sure, just like going out with a famous quidditch star while loyally keeping all your secrets and pretending to be in love with your best friend. At least I can drop that charade now, I guess."
"I… see."
Hermione nodded. "Anyway, I'm sorry, but I don't see any way to stop the girls from stunning you and enacting the harem ritual. It's not like we can just make sure nobody randomly stuns you every second of the day. And that's not even taking into account that Tonks is an Auror and can turn into literally anybody to get close to you."
"Yes… about that…"
"So I think the best thing for you to do would be to allow me to join them. I could stun you right now and bring you to them. Then you could make me your head harem slave and I could make sure for you that none of the other girls go too crazy."
"Hermione?"
"I know it sounds crazy, but I really don't think we can do anything el…"
"Hermione, listen to me."
"Yes?" Hermione asked insecurely.
"I have no problem with having a harem."
"What!?" Hermione screeched.
"You do realise I'm a teenaged guy, right?"
"But you never dropped any of the typical 'I'm a teenaged guy, I want a harem'-hints."
"I hesitate to ask, but which ones are that?"
"You know, like drooling at groups of Veela?"
"Doesn't virtually every guy do that?"
"Indeed." Hermione gave Harry a meaningful look.
"Moving on," Harry decided, "I'm sorry, but I didn't know about the typical 'I'm a teenaged guy, I want a harem'-hints."
"You could've still just asked me to become your harem slave, you know?" Hermione sniffed.
"I didn't know anyone wanted to become my harem slave, much less you of all people."
"You are Harry Potter." Hermione pointed out. "And what do you mean by 'me of all people'?"
"You are the girl who wants to free all House Elves."
"That's different."
"How so?"
"They are House Elves."
"…"
"You wouldn't understand."
"Right." Harry frowned, but decided it wasn't worth pushing for an answer. "So about that harem?"
"You are really sure you want one?"
"Yup."
"Can we still do the 'stun you and perform the ritual without asking you'-bit?"
"Why?"
"That way, as punishment for not asking your permission, the ritual will enforce complete loyalty and obedience on us, giving us a constant urge to do everything we can to please you. I was so looking forward to that."
"What about the others?"
"The others?"
"Are they looking forward to that part as well?"
"Of course they are." Hermione answered in a voice that brooked no argument. "Why else do you think they want to create you a harem?"
"I just assumed it was the usual reason." Harry deadpanned.
Hermione rolled her eyes. "Honestly, Harry. If the girls simply wanted to annoy you, don't you think they would all just marry you and become your regular wives instead of going through all the trouble to become your harem slaves?"
Harry blinked a couple of times. "If you say so…" After a few of moments of thought, he shrugged his shoulders. "Well, if you're certain, then I guess in that case we can still do the 'stun me and perform the ritual without asking me'-bit."
"Good decision." Hermione congratulated and made a note in a booklet she produced out of nowhere, before looking back at Harry. "The ritual I wanted to suggest to the other girls would also give all of us girls magical power to rival Merlin and Morgana, physical strength and durability to make a tribe of giants go green with envy and instant magical animagus forms into which we can partially transform in order to fulfil all your dirty Monstergirl fantasies. Wait… you do have dirty Monstergirl fantasies, don't you?"
"I do now." Harry replied with a confident nod.
"Great." Hermione smiled brightly, making another note in her booklet. "And with a harem full of magically and physically completely overpowered girls, you should have no trouble winning the war against Voldemort. And getting the Ministry to finally give Sirius a trial. If you need political support, I can adjust the ritual a little bit to also make each of your girls start to emit an allure similar to that of a Veela. That should ensure we can convince just about anyone to vote for just about anything."
Harry again shrugged his shoulders. "Sure, why not. In for a penny in for a pound."
"Wonderful sentiment." Hermione agreed. She made a final note in her booklet before it vanished to wherever it came from. "Then there's only one more thing."
"Yes?"
"Can we make the other girls all jealous by you having me call you 'Master' while all the other girls have to continue to call you 'Harry'?"
"Err…" Harry had to take a moment to digest that request. After brief consideration, he simply shrugged his shoulders for the third time and gave his soon to be head harem slave a benevolent smile. "Of course. After all, you were the only one to care about my wishes."
"Yay." Hermione cheered and proceeded to stun Harry point blank.
Suffice to say that both Harry and Hermione had a very good day that day. And a very good night that night. And a very good morning the next morning. And a… well, you get the idea.
Thanks for reading, I hope you don't consider this time we shared wasted. :-)