expression, noun
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.
この路地は蟻の門渡りで、太った人は通れない。
This alley is a very narrow passage; a fat person couldn't get through.
expression, noun
Euphemistic slang for the perineum, likening it to a narrow passage. Vulgar in tone; use with caution.
See also: 会陰
彼は下ネタで「蟻の門渡り」という言葉を使った。
He used the word 'ari no towatari' in a dirty joke.