【噬脐莫及】〖shì qí mò jí〗[One cannot bite one's own navel -- it is too late to repent; How can one bite one's navel? -- impossibility; It is as futile trying to remedy the situation as trying to bite one's own navel; It is useless to cry over spilt milk]

噬人瘈狗恩将仇，

脐脂自照折阳寿。

莫等双亲衰老去，

及时应令养育酬。

像咬自己肚脐似的，够不着。比喻后悔也来不及。Like biting own nave, can't reach. Metaphor too late to regret.同：噬脐何及。