「Cone-shaped, engorged with lightning discharge」during a rainstorm needs no explanation.
　「Bamboo on dragon」as a basket attached to the groin of an infected person for protection of the painful genitals, to apply and hold a poultice, and to contain sticky wads of purulent discharge. Bamboo strips were cut when green and pliable and woven into baskets. One of these uses was as a protective supporter, exactly as a codpiece was used in Europe and an athletic supporter with cup is used by male contact sport athletes today. The basket not only provided some protection against painful and unwanted contact of sensitive infected areas, but enabled a poultice filled with mashed grains and herbal treatments to maintain constant contact with the infected areas, provide deodorant functions, and hold absorbent batting. It is worth noting that 竜 uses elements of「standing erection with plugged orifice attached to penis」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.
　Note that this glyph is also used to depict a palanquin, a traveling cage for dignitaries representing the「dragon emperor」of China, and that thought may serve as a useful mnemonic. These same guys often needed medical treatment of this kind, too.
　「Kowtowing dragon」: a dragon might kowtow and bow down in homage only if caged. However,「bamboo like dragon」might make sense as something that captures a person in a place from which escape is nearly impossible (a cage on the penis and scrotum, caging one's dragon, and so on), since legend has it that dragons are clever, quick, strong, and difficult to elude (with some notable exceptions). Perhaps「dragon」was included simply due to the shape of its many strokes, resembling a CAGE, BASKET of「bamboo」lattice. It is unlikely that anyone believed a bamboo cage could contain an actual dragon (as we all certainly know, actual dragons are pretty tough…).

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: old variant of 籠|笼
Japanese: basket, hamper, cage, to be crowded, to be packed, to be complex, to seclude oneself, to be confined in, to be filled, to be heavy, to be stuffy, to be implied, to load, to charge, to put into, to include, to hang over, to shroud, to enshroud, to envelop, to screen
Unihan extended: cage; cage-like basket
EDRDG: seclude oneself; cage; coop; implied

Used within names (nanori)
ごめ