A person who goes on a straight date despite being flamingly homosexual. (This is typically but not exclusively used to describe a situation where the couple met online i.e. Tinder)
My friend Melissa went on this date with a guy from Tinder, and the moment he opened his mouth and called his female friend a queen…she knew he was a rainbow trout.
The Rainbow Trouser Trout... Put on your favorite episode of River monsters and pound two bowls of Fruity Pebbles. As soon as your wife complains about the show, vomit all over your dick and violently shove it down her throat whilst screaming "fish on" and pulling up on your dick like a fishing rod.