Both of them!

"Momo, Akemi, how about getting on all fours beside each other?" Denki asked as he dropped to his knees.

"Always ready for another round, eh, Master?" Akemi teased as she dropped to the floor on her hands and knees, as did Momo beside her.

"And whose fault is that?" Denki teased as he lined himself up behind Momo first. Momo only giggled a bit, not arguing in the slightest, instead simply wiggling her rear at him. Naturally, this provoked him into plunging his cock right into her waiting folds.

"Mmmnh... Well, you ARE easy to rile up, Master..." Momo crooned as her snatch clung to Denki's shaft. Denki couldn't argue against that as he began to finger Akemi, who bit her lip, pressing her pelvis back to generate more friction against her vaginal walls against his fingers.

"Oh yes... Master, right there..." Akemi gasped out as Denki kept fingering her. He then pulled out of Momo, and shifted, getting behind Akemi and thrust into her, while he inserted the fingers of his other hand into Momo's depths.

"Oh, this is pretty nice..." Momo giggled, using her vaginal muscles to squeeze and massage Denki's fingers. She was really good at it too, it was like she was trying to milk his digits.

He pistoned his hips back and forth into Akemi, and moaned, "You're both so tight... So velvety..." He swapped who he was fucking and fingering again.

"Ah..." Momo sighed in contentment. "I'm glad that we please you, Master..." she crooned as her pussy clamped down on him like a vice. He continued to fuck and finger them for several minutes, swapping every minute or so. Eventually, he reached a fever pitch within Akemi's velvety core, and grunted as he came, triggering her own climax as she cried out, savoring the feel of his hot essence flowing into her.

Denki pulled out, and wriggled his fingers in Momo's pussy until Momo gasped out, climaxing around his fingers as well. "...you girls are so hot when you cum..." he panted, and they turned weak smiles back towards him.