in (one's) cups
Drunk. When you're in your cups, foolish ideas have a peculiar tendency of sounding like excellent ones. He called to apologize the following morning, claiming that he had been in his cups when he made those rude remarks.
in your cups
while drunk. informal In your cups is now used mainly to mean ‘drunk’, but in former times the phrase could also mean ‘during a drinking bout’. Either could be intended in the passage in the Apocrypha regarding the strength of wine: ‘And when they are in their cups, they forget their love both to friends and brethren, and a little after draw out swords’ (1 Esdras 3:22).
1948 Vladimir Nabokov Letter I have received your letter… and can only excuse its contents by assuming that you were in your cups when you wrote it.