6 o'clock hot is where the temperature is so high, you can't do anything until 6:00pm in the evening - you just want to lay low and as close to air conditioning as possible!
Cedric The Entertainer often uses this expression to describe the Southern states of the USA.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi