Early electric guitar driven blues. We've got rolling piano, simple timekeeping drums and very basic bass. The guitar is also very functional here as well, pretty much only the piano gets a little showy besides the vocals. Howlin' Wolf's vocals are so gruff here. He would have been in his early 50's, and I think the recording captures that time, when a man has lived a lot of life, and may be beaten down a bit, but he's got plenty left in him if the reward is a fine woman. He sounds like he's issuing a challenge:
*I am a back door man. Once you go to sleep, I am going to sneak into your house and have sex with your wives. They will love me more than you, and in fact even if you catch me they will beg you to let me go free. Later, after I have had sex with them again, I will proceed to eat more than you possibly could, just to one up you in another way.*
He had some brass ones I tell you what.