Based on Chapter 19:
Alternate; W/incest; Unrequited
Sam/Nathan
Remember
"I don't remember any of that." Sam said quietly, avoiding the gaze of his brother and Bobby.
It was a lie, of course. What was he supposed to say? That he did remember it? There would be this whole weird thing. Even weirder if he admitted the fact that he had been into it. That inside of Lucifer being in control of his actions and Michael being present in Nathan's, that it had just been the two of them without Dean present.
He knew that it wasn't right, that having those kinds of feelings about his brother wasn't right. That him wanting to act on those feelings was in the same category as well as using the memory of what happened before to get off.
He was upset that they had been interrupted; that Lucifer and Michael hadn't gotten farther, which in turn would have meant that he and Nathan would have gotten farther.
Right now, instead of talking with Dean and Bobby, Sam wanted to go upstairs. He wanted to go into his brother's room and he wanted to do things to Nathan that should have sickened him, but instead turned him on. Things that he never would have thought about doing to another guy, let alone his brother, but had only ever done to Jessica. But now he wanted to do them to Nathan, all day and everyday and he wanted Nathan to do them to him too.
He wanted to entangle his fingers through his short and dark locks. Wanted to press his lips to Nathan's and explore his mouth with his tongue. He wanted to know what Nathan looked like without his shirt. To tweak Nathan's nipples and suck on them when they turned hard. He wanted to hold Nathan's ass in his hands, to squeeze those cheeks, to insert his fingers between those cheeks—he wanted his cock between those cheeks. He wanted to see Nathan's cock, to jerk it off, suck on it and have it inside of himself. He wanted to come inside of Nathan and he wanted Nathan to come inside of him. He wanted to feel Nathan's smooth skin under his finger tips. Sam wanted to cover every inch of his brother's body with kiss after kiss.
Sam knew that he loved Nathan, but he didn't think that he loved Nathan that way until now.