「Fluids flowing with tongue」suggests a wet mouth, not a common finding for very long among corpses—a mouth soon dries out without saliva flowing to replenish fluids, implying that the mouth belongs to someone alive and continuing to be so ON A DAILY BASIS, naturally.
「Flow, flowing」with「tongue, tongue actions」as a part of the ACTIVITIES required in the DAILY LIFE of many people. ONE'S JOB, some sort of job requiring skill servicing and sucking up to the master of the household who provided food, or, the job of slaving for a shaman pimp: see all the elemental combinations that clearly describe THE JOB of a service provider and her DAILY LIFE. Perhaps the origin of an expression similar to the English:「this job sucks」and so on, oral copulation with the boss man.
「Flow of fluid with tongue.」…and「tongue」elements are 'repeated bobbing and screwing with mouth, orifice,' as a means to complete the JOB of COMING ALIVE as one surefire method of REVIVING, RESTORING VITALITY, BRINGING BACK TO LIFE a flagging flaccid appendage until its「fluids flow」is by the liberal application of「tonguing」with「skilled technique.」
Water helps revive someone dying of thirst, keeping the person alive. Some cultures still today practice the oral insemination of sons in order to provide them with additional testosterone, a valued and highly sought steroid especially by professional athletes to build powerful muscles and a sharp mind, and this may give a hint as to whose duty it was to perform the daily tonguing…of course, the boys needed to swallow as well in order for the testosterone to be effective. See related glyph meaning「take a breather」(憩) and most any anthropological discussion of Papua New Guinea, or other ancient cultures. Clearly, steroids and testosterone give a person VITALITY and strength for ACTIVITY and LIFE, and the administration of the daily dose would definitely lead to the meaning DAILY LIFE ACTIVITY for those folks.「Flowing tongue, tongue actions」as a fine means of RESUSCITATING flagging interest.
「A blowjob a day keeps the doctor away? Of course, the same week that Michael Douglas links cunnilingus to cancer (although he clarified his comments a few days later), us ladies are given another reason to swallow. Guys have all the luck. Yesterday, we were informed that the nutrients in semen are roughly equivalent to a Gwyneth-endorsed protein shake. Yes, apparently dude's jizz includes such energy-boosting ingredients as fructose sugar, water, ascorbic acid, citric acid, enzymes, protein, zinc and others, according to HuffPo. While this could very well be a ginormous conspiracy by the patriarchy to get more oral sex, there is some proof in nature: Some female members of various animal species even consume male ejaculate regularly, like squid, flies and leeches. Squid, flies or leech ejaculate, I mean. Not human ejaculate. (Also, not [necessarily] the animals we want to emulate, per se.) Recently, our species has been catching on to the recreational imbibing of jizz: The bartender's handbook Semenology, as you can probably guess, features a variety of booze recipes mixed with the stuff. Another cookbook, Natural Harvest, makes the phrase 'down-home' recipes a double entendre.'」
[ https://www.cosmopolitan.com/sex-love/news/a13151/semen-protein-shake/ 2014-10-16 ]

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: to live; alive; living; work; workmanship
Japanese EDRDG: lively, resuscitation, being helped, living
Unihan extended: live, exist, survive; lively