「Standing swelled erection」with「penis plugging an orifice, sudden discharge, brilliant flashing, extreme heat, thunderous sounds」(or some sources say, a merging of「both hands on standing erect penis」) that also seems to glamorize the dragon-like 'power of the schwantz' with yet another euphemism referring to the Chinese DRAGON emperor and his affinity for anal intercourse with minors of either sex.
　「Biting fellatrix with bent penis」as a potential threat to the throne and its legacy, hence perhaps why orders were issued to the shamans and eunuchs to discover alternative methods of both intercourse and for prevention of fleeing biters who bit off more than they could chew, a solution that involved dis-integrating the feet of harem concubines.
　「Standing erection and plugged orifice attached to penis」as a condition that demands medical treatment or else internal scarring of the urethra will potentially close that opening, causing the passing of various fluids such as urine to become excruciating…with these various fluids in a colorful「sudden discharge」of blood, pus, gleet, seminal fluids, and so forth.
　It is significant that dragons are known to roar「thunderously」a trait also common among sufferers of gonorrhea when attempting to urinate, and that some dragons can even breathe fire, clearly a reference to an internal burning sensation likened to lightning that cannot be quenched by any means. Lightning strikes suddenly causing temperatures over five times what are believed to be present on the surface of our Sun, hot enough to change the surrounding air into plasma…it's electric, and the hottest naturally occurring condition on the Earth's surface, by far (now that the Chinese no longer crown an emperor). Dragons are often depicted in snake-like horned shapes resembling a penis with glans, another non-coincidence.
　Scholars claim that the element for「erection, swelled penis」is a dragon's head, imagined with a pointed nose or protruding tongue, whisker-like appendages, and ears or horns, and lower element is, if you prefer to believe so, a simplified and combined scaly「body」and long tail that now is a simplified form of「lightning, discharge.」

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: Japanese variant of 龍|龙
Japanese: dragon, naga, promoted rook
Unihan extended: dragon; symbolic of emperor
EDRDG: dragon; imperial

Used within names (nanori)
りう