To accomplish two tasks with only one effort.
To use only one action to complete two tasks.
The only true way to kill two birds with one stone literally is to have the following involved:
1)"Kill" two flightless birds with one very big stone. 2) Use one stone but recover it after each shot until two birds are "killed". 3)Wait until two birds are in close proximity and fire the stone from a bazooka. 4)Meteorite collision with Earth.
I have to go to Olvia's house, and you have to see your friend who is with her, let's kill two birds with one stone by both of us going
We can kill two birds with one stone if we go to walmart and get what you need as i get what i need.
When you like an average looking girl (girl A) with a hotter best friend (girl B) and you admit it to girl B and she tells you that girl A thinks of you as only a friend, but she (girl B) did like you, but now that she knows you have feelings for girl A, she wont go out with you.
I missed two birds with one stone, now I have an extreme case of blue balls.
To have sex with two women at the same time, and climaxing on their faces. Bird being another term for women, and stone relating to a man's testicles; more importantly the ejaculation.