They had talked about you for months, and it didn't take long for their discussions to turn pornographic. Nai would flip Vash, harshly pinning him to the bed.
"What if they could watch? Bet you'd like that, little slut." He teased. Vash whined at the thought, arching himself a little more.
"Miss her" he gasped. You'd barely spoken to them, never even spending the night- but that didn't stop them. "Want her, Nai, please"
"Oh? Does my little brother miss our Mommy?"
"Oh fuck~Mommy" Vash panted, fucking himself back onto Nai's cock
"She's not here, little brother." Nai's pace picked up desperately. He didn't want to admit but he missed you too. They fed each other's obsession, mentioning you constantly as if you were always there.
They were weird, whenever you did run into them. Vash more obviously, his usual easy going social nature faltering when he would run into you. You thought it was cute, wondering what made him so shy. Knives was more inscrutable, but you felt his stares from behind that hood.
It was Knives who started it, requesting to see you in one of his private chambers. The heat in his gaze made it clear what he wanted and you agreed gladly, admiring his handsome features.
You stepped into the room, watching as he took off his bulky robe. The close fit of his body suit left nothing to the imagination.
"You will allow my advances?" He asked, a bit stiffly. Almost nervous.
"Yes dear." You answered sweetly. The nickname threw him, but he recovered.
"I won't tell him if you want, I can be discrete." You reassured.
"You misunderstand. His is my twin, we are halves of the same whole. I know him as intimately as I hope to know you and you may not have one of us without the other. Is this acceptable?"
You freeze, processing. It made sense though, you had watched the twins together and all the weird little mannerisms clicked into place. "You fuck your brother?"
Knives winced at the crude phrasing. "I suppose."
"And he...wants me as well?" You clarified.
"Yes." Knives relaxed a fraction as you processed it relatively calmly.
"Call me Nai. Please." You sensed the begging under his tone. Something you could use.
"C'mere Nai," you cooed in your sweetest voice. He wrapped around you immediately, refusing to look at you but clearly needing the comfort. He mouthed at the crook of your neck.
"Mama" he whispered, barely forming the words.
"Oh, sweetheart, you need this, hm? Mama's here" You say, petting his hair. He clung to you, reaching under your shirt to palm your chest.
"Mama" he repeated, losing himself in the comfort.
"Will you take care of baby brother too?" He asked in a voice that sounded like a whole different person, hesitant and soft.
"Of course, baby, where's brother?" You asked. He reluctantly let go of you to press a communication button.
"Please, please, mommy" He whispered as he returned, holding you shamelessly.
A/N: Part 2 with Vash coming soon!