the horse is dead dismount

my husband and I used to argue weeks after a verbal agreement should have been over we were silly about it heckling and harassing each other over things that do not matter ridiculously egging and goading my husband told me a story about a soldier the soldier kept beating his horse after it had died his commanding officer said “the horse is dead, dismount”. now when the argument reaches a silly stage one of us yells “the horse is dead, dismount” this has worked to end our idiocy for the last fifty years.