Pleasure them both.

"You both heard of scissoring, right?" Kazuma asked them both.

"Yeah?" Megumin quirked an eyebrow.

"Why don't you both do so, but make sure you sandwich my dick between your cunts," he grinned at them.

"Oh, that sounds fun!" Aqua agreed easily. Megumin also fervently nodded, and with a bit of splashing as they moved into the position Kazuma requested, intertwining their legs and scooting their nether regions onto Kazuma's lap from either side, until they had Kazuma's erection sandwiched between them.

"Good girls," Kazuma moaned as the two started working their pussies against his shaft, moving them back and forth in opposite directions, and alternating that motion with up and down. It was a bit clumsy at first, but they quickly got in synch with one another.

"Oh... Thank you Master..." Megumin cooed, resting back on her hands as she worked her hips against Aqua's.

"You always did have good ideas," Aqua smirked as she worked in tandem with Megumin to try and get the three of them off.

"Dirty ones too," Kazuma agreed, before groaning in pleasure and bucking his hips slightly. "Both in terms of fighting, and in terms of sexy..."

Both of them moaned in agreement as they picked up the pace. It wasn't very long before they felt Kazuma's shaft throbbing between their pussies, and they screamed in pleasure as his seed erupted from his tip, reaching their peaks at the same time he did. His semen dispersed into the water, which made Megumin pout a bit.

"There goes a bit of slime I could get behind being covered in," she remarked, getting a snort from Kazuma. They spent the rest of the time in the bath getting clean, and then eventually got out.