As the expression implies, a very warm/hot place. This effectively communicates that it's uncomfortably hot, just as a whorehouse would be from the droves of people who would show up for "dollar night."
Sam: Why is it so warm in here. Dinner will cost us $100 each; you'd think they can afford air conditioning!
Nora: Yeah, it's hot as a whore house on dollar night.
Percy: "Man, look at these hands! They are calloused and bleeding from all of that yardwork!"
Samantha: " You let that shit get overgrown and it needed to be done. Stop acting like you're sore as a door on a whorehouse on a payday. Now fetch me some sweet tea!"
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."