「Mountain with widened orifice inside」may have been used for its shape of a wide hole inside a mountain. Nevertheless, neither mountains nor caves are all the same in shape or composition, every mountain is not necessarily associated with caves and caverns, nor are caves only located in mountains. As「glans and widened vaginal orifice」depicting clients and service providers or「clients with glans all alike」one can envision the CAVE of wonders, the shaman's place of business for「glans and wide array of vaginas」(i.e., CAVES).
Contrary to popular assumptions, nearly all caves were likely not formed as a result of erosion from underground springs or water flows within rock (ask yourself, how does water flow within rock before any rock has eroded?), but instead were formed while the entire surface of the planet was covered with deep water and under higher pressure than today by crushing the softer strata of the crust that were the「same depth horizontally」long prior to the appearance of any land or continents. The reason humans today can see caves associated with mountains, is that under mountains some cave fill has washed out of the crushed spaces, and not washed into them from outside, causing an entranceway to appear. Where there are no mountains, there still likely are both small and large caves within the Earth's crust, and those caves remain filled with the crushed rock that once formed solid strata:
「The processes generally cited in theories of cavern formation are corrosion [erosion by abrasive action] and solution. Neither of these processes adequately explains the presence of cave fill in many caves. A new concept in cavern formation involves a possible dis-integration process due to release of former high pressure on sediments that were being elevated from depths in which they were formed. This process can account for the relationship of cavern plans to joint systems, the generally horizontal development of caves, and other characteristics besides accounting for the formation of cave fill in place. This avoids the problem of explaining how cave fill can be transported into caves from outside. Application of the ory of dis-integration to problems of origin of dome pits in caves is discussed, and the possibility of this explanation of the formation of caves in non-carbonate rocks is suggested.」
[ https://creationconcept.info/cavfbrd.html 2023-05-17 ]
Caves have been discovered that were completely filled with crushed rock and silt, but if rapidly flowing surface water carried that silt and gravel into an empty space, how or where did the water flow enter and exit the subsequently filled cavern? would not the flow have been impeded by prior deposits, causing some empty space to always remain, if indeed erosion caused caves?

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: name of a mountain; cave; cavern
Japanese EDRDG: mountain in Gansu province
Unihan extended: mountain in Gansu province