Gabriel had a soft spot for the Winchesters despite everything, so he generally let their thoughts of anger towards him slide by without much retribution; he hadn’t ever expected more than fury or reluctant amusement in their thoughts when he crossed their minds in passing.
As it turned out, Dean in particular was a kinky little bastard even for a human; Gabriel found himself laughing when he saw an echo of what Dean was daydreaming about while jerking himself off, a fantasy of Gabriel and Castiel taking turns sucking his cock, lips occasionally brushing against one another’s until they were trying to kiss around him.
Amused by the new development in his pets of preference, Gabriel dragged a pile of pancakes over to dip his fingers in the maple syrup before drawing sigils on his breakfast table, summoning Castiel to his side to discuss events and laughing even harder when Castiel turned up, flushed red and sweating.
Apparently Gabriel’s appearance in Dean’s fantasies was a surprise, but Castiel’s wasn’t; Castiel had seen himself fucked - sometimes by Dean, sometimes by anonymous men, women, or gangs of both - and sucked and rimmed and bound, Dean’s current thoughts of their incestuous kissing around his cock being comparatively tame.
Gabriel asked why Castiel hadn’t told Dean that they could see his fantasies, and Castiel’s reply was simple; he’d meant to, the first time, but the second time he realised he actually quite liked watching.