Since sexual themes are heavily regulated or prohibited in most cultures, such a word may fail to exist, or to survive intact through the millennia. I suppose that local metaphoric and slang words, and contextually-altered expressions (like the generic "daydream" narrowed to that sense) replace it in many / most cases.

Same with words for copulation (highly restricted) and even for wooing / courting, which are also pretty universal activities since times immemorial.