Dirty blues songs were a popular sub-genre of Blues music. The reached a height during the 1930s, and had a revival in the 1960s. Sometimes known as Hokum, the songs employed risqué lyrics, often done through innuendo and double entendres. These kind of songs were generally supposed to be humourous, full of euphemistic tongue-in-cheek sexual references. However, with some dirty blues songs the lyrics were bold and to the point. They pulled no punches, and said exactly what they meant.

One of the most famous examples is the obscene song by Lucille Bogan called Shave 'em Dry (1935). Bogan is a renowned Blues singer, who in the 1930s started to write and sing more and more risqué songs about sex and drinking, culminating in Shave 'em Dry, which was one of her last recordings she made.

An example of the lyrics in Shave 'em Dry: 
"Want you to grind me baby, grind me until I cry. 
Say I fucked all night, and all the night before baby, 
And I feel just like I wanna, fuck some more, 
Oh great God daddy..." Oh great god indeed!

Weird Retro Facts: Legendary Blues singer Robert Johnson recorded what is seen as an example of the genre They're Red Hot (1937). The song was covered by the Red Hot Chili Peppers on their 1991 album Blood Sugar Sex Magik.

Robert Johnson is considered to be one of the most influential Blues musicians ever. His short recording career between 1936 and 1937, created landmark pieces of music, that went on to inspire generations of artists. The issue of his recordings on the 1961 album King of the Delta Blues Singers, brought Johnson to the world, and cemented his place in the pantheon of the 20th Century’s most influential musicians. Johnson died on August 16, 1938, at the age of 27. (Yup, he was one of the early members of the 27 Club.)  It’s thought that his guitar playing went from just average to phenomenal in a very short period of time, which lead to the myth of Johnson's supposed deal with the Devil at the ‘crossroads’.  A story that has gone done in music folklore and been picked-up and used numerous times since. 

The story goes that Johnson went down to the (now legendary) Crossroads in Clarksdale, Mississippi. There he met the Devil (disguised as a big black man), and how the Devil tuned Johnson’s guitar, played a few tunes and handed it back to him. In effect making pact Faustian style pact. It is believed that Johnson’s early death, and the rediscovery of his recordings many years later lead the creation and spread of the legend.

In 1936 Johnson recorded the song Cross Road Blues, otherwise known as "Crossroads". It's likely that this powerful piece of Delta Blues, and it's name added to the myth.

In 2002, Jack Black's band Tenacious D released the song Tribute. The video parodies the whole "pact with the Devil" mythology.

The 1986 movie Crossroads borrowed the Johnson's legend, to tell the story of a young musician who breaks free from his classical training to seek the blues, inspired by the myth of of Johnson and wanting to seek out a famed "missing song". Starring Ralph Macchio in the lead role, on his journey he comes across Willie "Blind Dog Fulton Smoke House" Brown, based on a real friend of Robert Johnson. On their journey of discovery they eventually come to the Crossroads, Where Willie reveals the packed both him and Johnson made with the Devil.