Literally: cow – drink – horse – eat
Alternately: To drink like a cow and eat like a horse; to eat and drink a huge amount.
Note: The first half can also be 鯨飲 (gei.in; “to drink like a whale”). The phrase can also be rendered, somewhat prosaically, as 暴飲暴食 (bou.in.bou.shoku; “violent/heavy eating and drinking”).
Random Youtube Link,
presented without comment.