Expressions (phrases, clauses, etc.), Ichidan verb
to cut one's own throat; to dig one's own grave; to cause oneself harm; to bring ruin on oneself
Idiomatic expression
人間楽ばかりしてるとダメになる。たまには、自分で自分の首をしめるくらい窮地に追い込むのもありだと思う。Comfort can spoil you. Once in a while, it can do you good to corner yourself.
Also written 自分の首を締める【じぶんのくびをしめる】