I'm looking for a specific story. I remember one scene in particular. Dean picks up a girl in a bar - I recall she wipes off her (red?) lipstick before they adjourn for privacy (I think in the restroom).

This is where I get confused: as I recall, Sam and Dean are reading each other's minds...or seeing through each other's eyes maybe. Sam is able to influence Dean's actions with the woman. I think it's a curse that makes them have this ability, and I think it ends in wincest.