Derek and Stiles went on dates, they cuddled, they occasionally kissed. They didn't have sex. It was an arrangement they had made fairly early in their relationship. Derek was repulsed by sex, even through his past relationships. Stiles was fine with it, he was probably asexual, he admits that Derek is handsome, but Stiles never felt a drive to have sex with anyone. It made for an awkward teen years, but they had made it through, and chose to use this time to just enjoy being around each other, doing things they both felt comfortable with.
Like now. Derek holds Stiles in his arms, although sometimes he does like when Stiles jetpacks, it's easier for both of them like this. Clad in their pajamas, for Stiles this meant only his boxers, as a werewolf put off a lot of heat. He had learned this when he woke up in the middle of the night the first time they slept in the same bed, drenched in sweat. Since then, a thin blanket and minimal clothing made for a comfortable sleep.
The quiet reigned, the air heavy with the satisfaction and comfort they both felt, just enjoying the heat and feel of the other.
Sex didn't need to be a big thing, so they didn't make it.
As they drifted off, they both thought the same thing.
Their relationship was perfect.