「Person with penis thrusting in array of vaginas, the same」vaginas as others are thrusting within, will eventually turn green as does COPPER: all the same, always the same result. Gonorrhea gleet is characteristically green (see 緑). Consequences are「person thrusting into penis spurting shaft with rod due to administrative management」of the infection discovered at the inspection stations located in the gateways of the walls surrounding the red-lined districts containing brothels.
「Metal same」and COPPER「remains the same」over a long period of time while oxidizing very slowly, after which the outer coating of oxidized copper, called「verdigris」(literally,「green color」), serves as a barrier that prevents further oxidization as long as sulfur compounds are not present (modern ecological problems of acid rain do cause further corrosion).
Nevertheless,「person downward thrusting a penis with spurts while digging」and「all the same, rod management」also suggest the widespread incidence of greenish-colored gonorrheal gleet that oozed from the shaft of so many thrusters, covering the reddish surfaces and forming a barrier against further activity,「officially losing one's rod and motion rights」by refused entry past the gateway inspection checkpoints surrounding the brothel districts. Copper starts out reddish, then turns greenish over time, not unlike males of the 'good old days.'
COPPER is a ductile metal that can be hammered, such as by a「person taking stance with downward thrusting motions」(left element),「widened and stretched」(right element), such as a「post-natal birth canal」into a new form that holds a lasting shape and remains the「same.」Copper is also one of the very few metals (another is gold) that can be found in metallic form occurring naturally as「native copper」and not only as a compound with other minerals, so the「metal that is the same」as before and as after smelting, and this led to it being easily found on the surface of the Earth and its use as the very first widely-used metal by human beings, the Stone-Copper Age predating the Bronze Age (bronze also contains copper, alloyed with tin and other metals for added strength).
Perhaps less than graceful but another strong possibility nonetheless is「metal」that resembles a「widened vagina.」…a human vagina in such a position will display「always the same」color, that of pinkish native COPPER, and perhaps was the source of the proverbial wisdom referring to ambivalence in regard to external skin color when selecting partners of differing racial or ethnic origin…something about 'all being pink inside' anyway, or so it goes.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: copper (chemistry); see also 紅銅|红铜
Japanese EDRDG: copper
Unihan extended: copper, brass, bronze cuprum