To (figuratively) slap someone with a slimy, stinky, wet trout; to admonish jocularly. (Internet chat)
Third person singular
Mid-80s BBS message boards, imitative of "thirty lashes with a wet noodle" only stinkier. Almost certainly from Monty Python's The Fish-Slapping Dance (1972), although the fish in that sketch was a halibut.
She got trouted for going off topic.
Everyone was trouting him for getting too silly.
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