S. R. Faruqi:

In this verse too, Mir's special dignity glimmers. The meaning of jurʿah-kash is a gulper-down, or a drinker of every drop. The age turns him into dust, but even so, in him the zeal for wine-drinking is such that his dust becomes the brick that is used to cover the cask of wine. The alliteration of ḳhāk , ḳhisht , ḳhum is also worth noting. There's no cause for regret in becoming dust, but rather a kind of stubborn pride.

In the verse there's also a sarcastic aspect-- that as long as I was alive, I used to get wine only by the drop; but when I became dust, then I was seated atop a cask. There's also the point that since the brick does the work of covering the cask, it follows that I love wine so much that even after death I am covering the cask, so that the wine wouldn't be wasted. The style of the verse is outwardly regretful, but behind the veil the poet's pride is showing.

['Umar] Khayyam has often used this kind of theme [in Persian], but in Khayyam the principal aspect is always that man has to die and rot away into dust. His style is sorrowful, didactic, and dramatic. His tone is dignified, but there's no sarcasm directed at himself, or at the age. Rather, there is silent mourning at man's destiny. And the truth is that Mir has not used this theme (that is, to die and become dust and then become something useful for wine-drinking) better than Khayyam has. But the thing in which Mir has outdone Khayyam is his sarcastic style and depth. Khayyam has more didacticism. If his style were not dramatic, then because of its didacticism his verse would remain unsuccessful:

'Yesterday I flung down a clay cup on the stone.
This rakishness was done by me because I was extremely drunk.
The cup said to me, in the 'tongue of its condition',
'I was like you; you too will [one day] be like me'.'

Khayyam's theme, in comparison to Mir's, is certainly somewhat broader, and the melancholy didacticism in it is fine. But in some aspects Mir's verse isn't less than Khayyam's. Sayyid Muhammad Khan Rind, a pupil of Atish, has used Mir's theme and aspect in his own way, but he hasn't achieved the same effect:

mai-kash vuh haiñ kih ḳhāk bhī kar de gar āsmān
kāsah hamārī ḳhāk kā jām-e sharāb ho

[that one is a wine-drinker who, even if the sky would make him into dust--
'may our bowl of dust be a cup of wine']

[See also {126,5}; {239,7}.]

FWP:

SETS
MOTIFS == WINE
NAMES
TERMS

It's indeed a very Khayyam-like verse. Or as we experience it in English, a very FitzGeraldian verse.

Note for translation fans: Since the opening of the wine-cask is covered by a brick, it would be fun to try to make use of 'blockhead' for nadān . In a literary translation it could perhaps be made to work.