HORSING AROUND

backing the wrong horse 

beating a dead horse

putting the cart before the horse 

champing at the bit

changing horses in midstream 

having a charley horse 

betting on the dark horse 

he eats like a horse 

he is feeling his oats 

straight from the horse's mouth 

being as healthy as a horse 

get off your high horse 

hold your horses 

let's hoof it out of here

we were just horsing around

that's a horse of a different color 

she has no horse sense 

well, if wishes were horses 

don't look a gift horse in the mouth 

you can lead a horse to water but you can't make it drink 

been working like a horse