In one's cups

[T]he natives were an honest, social race of jolly roysterers, who had no objection to a drinking bout, and were very merry in their cups.

They grew only the more sober in their cups; there was no confused babble nor boisterous laughter. They sucked in the joyous fire of the decanters and kept it smouldering in their inmost recesses.

[H]ere he gambled, there he drank; and in his cups every virtue dissolved.

The woman on the other hand is in her cups swigging from one wine glass while another stands at her elbow.