If when my wife is sleeping
And the baby and Kathleen
Are sleeping
And the sun is a flame-white disc
In silken mists
Above shining trees,-
If I in my north room
Dance naked, grotesquely
Before my mirror
Waving my shirt round my head
And singing softly to myself:
"I am lonely, lonely
I was born to be lonely
I am best so!"
This behavior isn’t what society would expect from a man, let alone a doctor and a father. The use of “grotesque” in this instance refers to uninhibited passion completely divorced from the constraints of society. In this phrase, Williams is coming to terms with his own barbarism, the part of his soul that has been suffocated and rejected by a domestic lifestyle spent delivering babies and providing for a house of women. 
 Also a poet precursor to Billy Idol: 

Danse Russe