very narrow passage; tight squeeze
Literally 'ant's gate crossing'; used for a passage so narrow one must edge through sideways. Often humorous or exaggerated.
This alley is a very narrow passage; a fat person couldn't get through.
perineum; taint
Euphemistic slang for the perineum, likening it to a narrow passage. Vulgar in tone; use with caution.
See also: 会陰
He used the word 'ari no towatari' in a dirty joke.