It's hypnotic.
It sets the mood for the lyrics so well.
Played by Herbie Flowers, it is doubled by him playing it on stand-up acoustic bass & then later on a Fender fretless Jazz bass.
It has the thump of stand-up with the smooth of the electric. Fantastic idea.
I remember when radio around here didn't play the second verse because of the "givin' head" phrase. Probably took 5 years before they got over thst..