As「rod within the youthful orifice」「orifice, mouth bobbing on woody」「seeds at woody stalk tip with orifice」and「gonorrhea mouth, orifice」shared among a tribe of early humans, clearly the result will be to COMBINE DIFFERENT SUBSTANCES SO THAT THE CONSTITUENT PARTS ARE INDISTINGUISHABLE FROM ONE ANOTHER, swapping our 'precious bodily fluids' by BLENDING them all together and MIXING, so that quite soon the obvious result gradually was understood after everyone became infected. Perhaps describing the resigned acceptance of the ultimate outcome in those 'good' old days with no antibiotic treatments, creating a type of HARMONIZED acknowledgement of the inevitable SOFTENING (not turgid) and CALM conditions (no longer hopping on one another) after the whole tribe was stricken: soft, fragile, weak, poorly built, insubstantial. Agreement about what actions to take, or not to take, ALL HAVING THE SAME OPINION AND FEELING whether related to goodness or related to adversity. While today most folks inject modern usage of「harmony」into their thinking and consider it to be a good thing, in fact HARMONY formerly was a neutral concept, a 'relationship characterized by a lack of conflict or by agreement' [ https://www.thefreedictionary.com/harmony ] by not fighting or shifting blame (委) any longer, but without stating the cause or reason for the calm resignation that underpinned that harmonization.
HARMONY means that everyone is singing the same tune in a simultaneous combination of sounds, but that may well have been wailing sad songs by the tribe entreating divine entities for intervention rather than happy caroling of praise and joy.
Old glyph elements「grainy tip」with「blowing pipes」(龢) that together make little if any sense, but seem reasonable as「person's taut erect rod with many different orifices and rod in many spread legs, with gonorrhea」swapping our 'precious bodily fluids' by BLENDING them all together, like it or not. As「gonorrhea mouth」elements perhaps were the source of the later English expressions「I blew it!」「Don't blow it」「Sucker!」「Calm before the storm」and others that relate making a big mistake and disaster with the act of blowing and/or sucking.
Historical references by the Chinese to JAPAN in this case was clearly intended as derogatory, in line with most other references to Japan by the Chinese throughout history, and continuing today for that matter. In addition to infection, may be suggesting that the Japanese「blow pipes with seeds at stalk tip」as an obvious reference to performing fellatio with one another, i.e., a bunch of cocksuckers.
Another replacement glyph reverses the order of elements (咊): meaning to overcome distrust or animosity, appease. Regain friendship or goodwill by pleasant behavior. To make or attempt to make compatible [ https://www.thefreedictionary.com/conciliation 2013-08-14 ]…indicating that an「orifice or mouth at tip of a woody」is a surefire method of BEING ON GOOD TERMS, being KINDLY…after all, what are friends for? obviously, if an oral or other orifice is willing to continue with an infected woody, there must be some degree of harmony and good terms.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: harmonious; to mix together; to blend; soft; warm; cap (a poem); to respond in singing; and; together with; sum; union; peace; Japanese
Japanese EDRDG: harmony, Japanese style, peace, soften, Japan
Unihan extended: harmony, peace; peaceful, calm

Used within names (nanori)
あい　･　いず　･　かず　･　かつ　･　かつり　･　かづ　･　たけ　･　ち　･　とも　･　な　･　にぎ　･　まさ　･　やす　･　よし　･　より　･　わだこ　･　わっ