Stiles didn't know enough about being an omega, let alone being a claimed omega, to really make sense of how everything felt. How he just wanted Derek all over him all the time. How he wanted him inside him, knotting him, constantly. Perhaps the newness of their relationship, the coming together of mates, especially an omega and an alpha, especially a newly presented omega... Perhaps they were just very compatible. There could be a million reasons why Stiles needed Derek all over him all of the time.
He didn't even consider the bite, even though he felt something heavier and more tangible between them now, a bond more solid forming.
Stiles was watching over his shoulder when Derek fought back his shift. His eyes widened, a tiny gasp escaping his lips at the shock of desire that rolls through him. He could see it almost like a shimmer around his mate, the shape of his wolf, the full form- He knew it wasn't going to be now, it wouldn't happen right now, but-
"Oh God-" Stiles mewled when Derek's face pressed against him, knowing his teeth were sharp and bare and close to his skin. Derek's tongue could be the death of him, the way he lapped at Stiles, licked him.
Goosebumps followed Derek up Stiles' spine, another little moan falling from his lips when Derek's fangs rested against his neck. He'd been claimed. Derek had claimed him. He was Derek's now.
His heat was incredible, rolling off of Derek as he lay himself over Stiles, who tried desperately to spread his legs further. Not that he needed to-
Stiles sobbed out at the pleasure of Derek's thick length sliding into him. Slow and controlled. It was even worse like that than it was when they went hard and fast. "Derek, please-" he heard himself whimper. "Oh God. You make me feel so full. So full." Stiles turned his head, his eyes wide as he gazed up at his mate. "You wanna fill me up more? I want you to knot me. I want to be full of your come. I want to know how good our contraception is." Like Derek, Stiles was trembling with the restraint of not moving. "I want your baby in me."
The gradual drag of Derek's cock inside him was making Stiles clench, the way his head dragged against Stiles' prostate made him almost weep. "Don't stop. Please don't stop. I need you. Need you to fuck me. I'm yours. I need you to fuck me." He momentarily thought about ramming back against Derek, riding him from this position, taking control. But no, that wasn't what he wanted, that wouldn't satisfy him. Right now he wanted to submit. He wanted to be a good mate for his alpha. "Please? Please?"