Make Megumin a bisexual voyeur.

"You like the taste?" Kazuma asked.

"Y-yeah," Megumin admitted with a blush.

"Well then, why don't you and Darkness lick off each other's faces?" he suggested, and Darkness turned to Megumin with a grin, Megumin turning to look back at Darkness, blushing heavily as she hesitantly considered the idea. Again, Kazuma had just started to contemplate just snapping her into trance again, before both of them leaned forward and started to lick each other's faces.

"Good girls," he chuckled again. He wondered how far he could push Megumin without needing to use her trance. Probably just a bit beyond the current comfort zone. Soon, they were done, and looking at him again. Kazuma snapped his fingers, and asked Megumin, "Answer this question honestly. Are you straight or bisexual?"

"I'm straight, but maybe a little bi curious," she informed him after waking up from trance.

Snap. "From now on, you're completely bisexual," he ordered. She came out of trance again, blushing heavily as her gaze roved over Darkness. Snap. "You're a voyeur. You love to watch me fuck other girls."

She nodded, and woke up again. "Oh, are you gonna fuck me with her watching?" Darkness asked excitedly.

"Most definitely," Kazuma smirked.