Tell them the truth of the matter with some help.

'I'm so sorry sir!' the succubus girl spoke to Kazuma through telepathy, startling him a bit. 'I tried to come give you your dream, but I wasn't expecting a spirit barrier, and I couldn't even break in and reach you! Just let them destroy me and pretend you don't know me, so they don't come after the shop!' she pleaded.

'...yeah, no, and don't worry, they won't,' Kazuma thought back, not sure if the telepathy was gonna work both ways, but trying it nonetheless. 'I'll make sure of it.'

He then walked up to Aqua and whacked her upside the head. "Kazuma!?" Megumin asked as Aqua fell over, and the Succubus shot back to her feet, confused, and Kazuma stepped in front of her.

"Don't tell me she has you under her sway already!" Aqua demanded.

"Actually, no," Kazuma deadpanned. "She's here because I invited her here."

"...what?" Megumin blinked.

"Then you were under her sway earlier in the day while you were out!" Aqua pointed.

"If that were true, then why am I not already drained of vitality?" Kazuma deadpanned.

"She... She could have wanted a more private place with no witnesses so ordered you to invite her to your home!" Aqua rallied, giving a pretty sound argument actually.

"...true, but that's not the truth of the matter," Kazuma replied, pinching the bridge of his nose. "They run a shop in town, and only take a little vitality from men who actually ask them for erotic dreams, because it's safer than constantly trying to attack adventurers, and I thought I'd give it a try."

"...why the hell would you do that when you already have... Well you know?" Megumin asked, but careful not to expose anything about the Sex Note.

"To add a little variety to my sex life, duh," Kazuma rolled his eyes.

"She's just making you make excuses for her!" Aqua accused, pointing. "Devils running a legitimate business!? I never heard of such a thing!"

"Because they don't openly advertise it, because of bigoted morons like you, genius," Cremea crossed her arms.

"Huh? You know about it Cremea?" Kazuma asked.

"Yeah, and you guys can be sure that we aren't under her sway, we're women," Fio added. "Kyouya found out about Devils in town, and investigated with us, and we ended up finding out about the shop, and when he got the story, he decided to leave the Succubi be."

"...so he actually CAN listen to other sides of issues, he just chose not to when first encountering me, huh?" Kazuma groused, getting a snigger out of Fio.

"He CAN be a little selective as to who he listens to and when," she agreed.

"...fine, go have fun with the little devil then!" Aqua huffed.

"I do believe this goes without saying, but not a word about the establishment unless you're actually sending a prospective customer their way, and not an action against it!" Kazuma told his party/harem.

"Fine!" Aqua huffed, crossing her arms and storming off.

"...come on, we have unfinished business," Kazuma told the surprised succubus, and wrapped an arm around her, walking her to his bedroom.