I smell thirty cows

A feeling of great happiness and hunger

ME:How do you feel
Him:I smell thirty cows
Me:What do you fell like eating
Him:pant

i can smell your soup from here

Another way to say that you understand what someone is saying.

Ex: "Did you see that episode of The Walking Dead last night?? It was insane!"

"Ya! I can smell your soup from here!"

i smell a moose

A common phrase said when it is snowing outside, typically said in southern states (where people don't actually smell moose)

(Guy1)"Hey man, I smell a moose!"
(Guy2 reply)"Get all the milk, eggs, and bread you can! They are callin' for a half inch tonight!"

I smell bacon

Means there is a cop near by

You are about to light a joint. Your friend sees a cop crossing the road toward you, and says "I smell bacon"