「Erection within burial corpse」as DO NOT, NO NECROPHILIA that for most folks needs no explanation as DANGERS RESULTING FROM NOT WASHING THOROUGHLY and as SPREADING INFECTIOUS DISEASE. What these elements have to do with the no-longer-integrated feet of a deceased service provider is anybody's guess, yet, the given meanings would still apply to「erection rod with vertical reciprocating motions within arch of foot」of a beautiful corpse, albeit with a bit of rigor mortis. Note that both a rod and another erection CANNOT both simultaneously access a single no-longer-integrated foot, even that of a living service provider, although it must be imagined that some folks in dynastic China attempted this very scenario, hence the creation of this glyph: DO NOT attempt this action meaning DO NOT as in something that should NOT be done, DO NOT join in with this one. Elements as「arch of no-longer-integrated foot」or「end-to-end extreme tension for long time causing gasps」with「erection」(the next one, in this case?) together with another「rod in vertical reciprocal motions」superimposed and inserted within the same foot without a thorough cleansing between accesses by different clients: SPREADING INFECTIOUS DISEASE.
　Not too likely, but some suggest a WARNING NOT to hang any such loosened binding cloths「between the walls」prior to a thorough washing due to the horrendous odor, as this element has been replaced by「stinky, loose and dripping, STENCH CLOUD (厶)」in modern glyphs SPREADING INFECTIOUS DISEASE…keep them outdoors—in either case, a WARNING NOT TO DO without washing first.
　Of course, the capitalist way is to MAKE THE MOST PROFIT by cutting costs and corners, so not washing between clients enabled the workers to remain in service with the next client, reduced the cost of cleaning supplies and laundering, and increased the revenue stream by substantially reducing the mean time between clients (years ago, MTBF formerly was the acronym for the shaman's calculations of 'mean time between fuckers' or so it is rumored, with 'failures' replacing the final word after learning of the DANGERS RESULTING FROM NOT WASHING THOROUGHLY).
　Not as likely, but perhaps two warnings: DO NOT use an archery bow while pointed vertically (the arrows tend also to return vertically in those cases, striking the shooter or a comrade), and DO NOT use quick movements to one side while an arrow is nocked (experience shows that the arrow tends not to follow the bow due to inertia, and subsequently letting loose may injure the shooter or a comrade). Could be the source of an English expression, although it makes little sense since it originated during the days of bows and arrows,「to shoot oneself in the foot」that later requires a「bound foot」until it heals…most likely, the expression formerly intended was「to shoot oneself (with an arrow 矢, the sick penis of another) in the foot」of a Chinese service provider that contained infectious bacteria, such as Neisseria gonorrhoeae, as another quaint coded expression brought back to England by the opium drug peddlers which commoners in London could not comprehend: the speaker contracted a case of the clap. This expression is equivalent to「stepping on my own penis」with variants, a scenario that also is not anatomically possible except in the most extreme cases, hence most likely relates to the same conditions as described above when using a Chinese service provider's contaminated no-longer-integrated foot, but let's hope not related to schtupping (ejaculation into a birth canal or other attainable orifice) the anus of a corpse, although necrophilia simply means the 'love of death flesh,' common to both no-longer-integrated feet and cadavers, seemingly.

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: not
Unihan extended: not, negative
EDRDG: dollar