A stream of golden liquid comes streaming from the genitalia onto or into another person. For sexual pleasure, humiliation, or cleansing purposes. Often associated with 'Golden Oldies' because it is such a primitive thing to do. However, it predates the golden oldies. It predates the wheel. It probably predates the universe.
Unga: unk unk booga unk bog stump!
(I gotta take a leak babes, and I'm super-horny, and you smell a lil funky. Can I give you a golden shower)
Nunga: unk lunga stumhu plk
(Oh my god you're such a cocky bastard! That's so sadistic, primitive and sick, you perve! I'm staying at my mothers! Don't even dare calling me!)
Many centuries later
Jon: my dearest lover. Thy hair floweth down thine supple back as urine down the recipent of a shower of gold
Dee: ew. I feel sick now. Goodnight