「Flow that is narrowing, becoming smaller, small」is SHALLOW, and water that makes the SOUND OF MOVING WATER…think of the spurting sound of water from the end of a garden hose when a thumb is placed over the exit hole. Being too tired or weary to put out a full effort after battling repeatedly, or,「swinging dog penis, twice」as subsequent copulation attempts with bitches in heat, both being only a SUPERFICIAL effort, just for the sake of appearance, and of course with a「flow that is narrowing, becoming smaller, small.」…and emit babbling sounds as a result of the Coolidge Effect kicking in too many times.
　Additional ability to continue sexual intercourse by males after the addition of another female, known as the Coolidge Effect:「Males of most mammalian species show a strong desire towards variety in sexual partners. In the laboratory, this phenomenon has been referred to as the 'Coolidge effect.' It was first observed among rats. The same effect is even more striking in farm animals such as sheep and cattle. Studies based on self-reports among human subjects found that partner variety is of greater interest to male adolescents, male college students and male adults…」
　　[　for a full discussion, including the effects of dopamine on the brain, see the European Journal of Human Genetics:　https://www.nature.com/articles/5201763 2023-05-19　]　
　After schtupping (ejaculation into a birth canal or other attainable orifice) to exhaustion and reaching the natural climax limit with the same partner in a single session, a male can revive his flagging schwantz as soon as a new female partner joins the session, due to the effect of an instantaneous release of additional dopamine upon the sighting of her orifices or the first sensing of her pheromones by the male. The「power of an orifice」joining in participation to provide additional erections is evident to those who have experienced this phenomenon, or witnessed「flow of fluids with two dogs wagging baculums.」

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Chinese: shallow; light (color); sound of moving water
Unihan extended: shallow, not deep; superficial
EDRDG: shallow; not deep; superficial