A CLAM,「lower life form」with a shell having two sides that「fit together」nicely. Moreover, clams normally live juxtaposed in large colonies, reproducing by broadcast spawning, the release of eggs and sperm into the water seasonally, joining gametes of all sorts of physically nearby and biologically closely-related individuals in an incestuous display. A「worm with both sides joining together」within the shell halves. hamaguri live in brackish waters, mixed salt and fresh sources, where「both sides join together.」In Japan, hamaguri traditionally are eaten on 'girl's day' of March 3rd, perhaps due to their similarities, both being as 'juicy as a freshwater clam' and with fluted-shaped meat internally. How that relates to the elements「loose dripping orifice with consent, joining together, person's rod with orifice」is anybody's guess.
　FROGS and TOADS unite,「join together both sides」orifice-to-orifice (both males and females possess a cloaca), mixing it up in clusterfucks:「loose dripping orifice and joined, combined, united, consenting」as a FROG or TOAD…not a reptile as are snakes, rather, an amphibian:
　「In explosive breeders, the first male that finds a suitable breeding location such as a temporary pool, calls loudly and other frogs of both sexes converge on the pool. Explosive breeders tend to call in unison creating a chorus that can be heard from far away. …Mate selection and courtship is not as important as speed in reproduction. …At the breeding site, the male mounts the female and grips her tightly round the body. Typically, amplexus takes place in the water, the female releases her eggs and the male covers them with sperm. Fertilization is external.」
　　[　https://en.wikipedia.org/wiki/Frog 2013-08-26　]　
　Frogs and toads also hibernate during winter by burying themselves in muck, and clams do so most all the time.

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: frog; toad; clam
Japanese: frog, common orient clam
Unihan extended: clam
EDRDG: clam