2) From now until whatever time the fat broads you live with return to the house.
When the cops started knocking on the door of the cocaine storehouse, Pete and Tony jumped out the window and ran until the cows came home.
"Hey dad, when are we gonna be eating dinner?"
"Not until the cows come home, son. Where the hell are your mother and sister? I'm hungry too."
someone might stay up at night or out at bars, nightclubs, discos etc.
The origin of the phrase goes back to
a time when people were familiar with the time cows came home
(in the very early morning... 4 - 5 a.m.) because they wanted to be milked.
Person 2: Really? how long?
Person 1: We are staying out until the cows come home!