That'd be pretty nasty for all three. Plus, even if it's nothing more than an inappropriate, horribly disturbing kiss, they're all going to have that moment of worrying that the demon might do more, and knowing they can't stop it. Which would be worst for John, of course, because it's his body and his son. But pretty nasty for Sam. Bad things happening to his brother, Sam's massive daddy issues, "I should be able to help him with my incredibly unreliable telekinesis that's only worked once" issues.

I know what you mean about being nice to the Winchesters. The best I managed was that Top Gear crossover, where Sam and Dean got to hang out with Jeremy one night and drink and pull weird pranks, and nothing bad happened to them the entire story. That was nice.

You could be nice if you aimed small enough? Like Sam and Dean having a really sweet brotherly moment that doesn't center around horrible things happening? Or Sam has a one-night stand with a girl who in the morning gives him a kiss goodbye, calls him sweet, and leaves without suffering any horrible fate whatsoever.

Er, part of my brain may be trying to write Sam/Riona now. In a way that doesn't actually involve you suffering any horrible fate whatsoever (although may suppose you've seen less of the show than you have for plot reasons). But my mind won't quite believe that your name isn't Riona Leon-Hart.