Is there a noun specifically for the physical feeling of sexual pleasure?

"Pleasure" is very general. The word "arousal" refers to the "evocation or awakening of sexual pleasure"; "gratification" refers to the feeling that comes after, as does "satisfaction"; "lust" the desire for but not the thing itself; "orgasm" is the climax of sexual excitement but not the excitement itself. As so it goes on, through every relevant entry in the thesaurus.

Isn't there a simple word for the sensation of sexual excitement? A specific opposite of pain?

Sorry if the answer is uberron. But I just can't remember.