in all of this shamefulness I think we need to remember the glorious line:

do I dare eat a peach?

Considering Eliot's aversion to all things "womanly" (as he certainly had a problem with Vivienne's hypermenses . . . probably Endometriosis of some sort), I think this poem is USING sex and the desire, lack of, etc. to get at a larger problem of action.  Especially Generative action.