How I laughed at my mother's false teeth, As they foamed in the waters beneath

How I laughed at my mother’s false teeth, As they foamed in the waters beneath.
But now comes the reckonin’
It’s me they are beckonin’
Oh, I wish I’d looked after me teeth.
(a) Explain “But now comes the reckonin’, It’s me they are beckonin’.”
(b) What do you mean by ‘reckonin’, here?
© When did the poet laugh at her mother’s false teeth?

(a) The poet has to pay for making fun of and laughing at her mother’s false teeth as now she also needs false teeth.
(b) ‘Reckonin’ here means settlement of account.
© The poet laughed at her mother’s false teeth when her own teeth were in a good condition during her childhood.