Not a snake, worm, or insect actually, a CENTIPEDE is an arthropod.「Worm that chews, gnaws until kinky」refers to the manner in which the animals chews, masticates its food, being not unlike a renegade fellatrix or service provider (right element):
「What centipedes actually eat is not well known because of their cryptic lifestyle and thorough mastication of food. Laboratory feeding trials support that they will feed as generalists, taking almost anything that is soft-bodied and in a reasonable size range. It has been suggested that earthworms provide the bulk of diets…」
[ https://en.wikipedia.org/wiki/Centipede 2013-09-14 ]…earthworms that slide with slime into soil where they dwell, excreting more night soil.
Perhaps referring to the manner in which the animal's legs all must immediately「draw near and accede at once」to the motion of the leg in front. Each pair of legs is slightly longer than the pair in front to avoid tripping over its own legs when scurrying.
「Snake, worm, insect, arthropod」of a「bastard」refers to the manner of insemination, with a bastard as offspring from an unknown father (mothers in most cases are self-evident, even those of humans) being not unlike a renegade fellatrix or service provider:「Centipede reproduction does not involve copulation. Males deposit a spermatophore for the female to take up. In one clade, this spermatophore is deposited in a web, and the male undertakes a courtship dance to encourage the female to engulf his sperm. In other cases, the males just leave them for the females to find.」
[ https://en.wikipedia.org/wiki/Centipede 2013-09-13 ]
Animal discharging venom from both ends:「Forcipules are a unique feature found only in centipedes and in no other arthropods. The forcipules are modifications of the first pair of legs, forming a pincer-like appendage always found just behind the head. Forcipules are not true mouthparts, although they are used in the capture of prey items, injecting venom and holding onto captured prey. Venom glands run through a tube almost to the tip of each forcipule. …The final segment bears a telson [for venom injection] and includes the openings of the reproductive organs.」
[ https://en.wikipedia.org/wiki/Centipede 2013-09-14 ]

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: a centipede
Japanese EDRDG: centipede
Unihan extended: a centipede