What is the logic behind the similar sounding expressions 後へ引く and 後を引く? Are they idioms? Apple dictionary lists these examples:
後へ引く
もう後へは引けない
'It's too late to turn back now.'
'We're in too deep to back out now.'
後を引く
1 影響が残る
傷の痛みがいつまでも後を引いている
'The pain of the wound [won't go away / still lingers].'あの事件の後遺症がいまだに後を引いている
'The aftereffects of that incident are still being felt.'
2 次々に欲しくなる
このクラッカーは食べ出すと後を引く
'Once I start eating these crackers, I can't stop.'
The idiomatic meanings don't quite fit the individual words or similar idioms (eg 潮が引く "the tide goes out" or 事故が後を絶たない "there continue[s] to be [no end to the] accidents").