I too beneath your moon, almighty Sex,
Go forth at nightfall crying like a cat,
Leaving the lofty tower I laboured at
For birds to foul and boys and girls to vex
With tittering chalk; and you, and the long necks
Of neighbours sitting where their mothers sat
Reading with clues from the rest of the poem ( “reared To Beauty” ,  “it is my own” ), it’s reasonable to say that this tower refers to Millay’s poetry and building the tower as pursuit of a “high art” form (high-lofty-coincidence?). 
 During the day, the poet labors at writing poetry, which is a far cry from the dirty, smutty world of sex and lust she escapes to at night. 
 But as we read on, we’ll see that these two worlds are intimately connected. 
 It’s common for critics these days to read obscure poems as apparent references to the poet’s relationship to writing poetry. A great example is  Adrienne Rich ’s reading of  Dickinson , comparing herself and poetry to a hunting rifle and its owner. 

I Too Beneath Your Moon Almighty Sex