All Night in White Stains by Aleister Crowley.

“No whispered sigh,
No change of breast, love’s posture perfectly
Once gained, we change no more. The fever grows
Hotter or cooler, as the night wind blows
Fresh gusts of passion on the outer gate.
But we, in waves of frenzy, concentrate
Our thirsty mouths on that hot drinking cup
Whence we may never suck the nectar up
Too often or too hard; fresh fire invades
Our furious veins, and the unquiet shades
Of night make noises in the darkened room.” [via]