Fig.: to look at someone in an amorous way

Anthony, just divorced, kept casting sheep’s eyes at every girl at the party

Antonio, divorziato da poco, faceva gli occhi di triglia a tutte le ragazze presenti alla festa

Did you see those two at the restaurant last night? They kept making sheep's eyes at each other all night long across the table to the point of becoming totally pathetic and absolutely ridiculous

Hai visto quei due ieri sera al ristorante? Hanno continuato a guardarsi con gli occhi da pesce lesso per tutta la sera, fino a diventare del tutto patetici e ridicoli

This idiom, whose first known use dates back to the early 1500s, was probably inspired by the soft, tender look of sheep's eyes