In some current American slang it is a reference to male ejaculation; however the phrase has a very long history covering most of the time that muskets have been in use up to the present. The wad is a piece of paper put in the muzzle along with the projectile and gun powder. If the shooter is too hasty -- say in a tense battle -- they may not include the projectile. The result is a fire without the intended bullet; only the wad will fly out...a wasted shot. Hence, "shooting your wad" can mean expending your energy fruitlessly. The OED also references the wad as in a roll of paper money; in this case "shooting your wad" means blowing all your cash at once.
the origin of this idiom mean fail or succeed
To be exposed
Origin "up a storm"
It's GET YOUR DUCKS IN A ROW. It's from duck hunting -- you get your decoys all out on the lake in a row to attract the ducks so you can shoot them.
That's not an idiom - it means exactly what it says - there are twelve months in a year.
The origin of the idiom 'go the extra mile' is from the Bible. It comes from a parable of Jesus in the 5th chapter of the book of Matthew.
The idiom a feather in your cap is of English origin. It derived from Indian warriors who added a feather to their head gear when they killed an enemy.
It is a slang term from the 1930's, origin not known
Palestinian and Persian
the jazz era
grab a bite
It was in 1960 in America
To hope for the best
Meaning he will help you out.
you found it
It is just an idiom and has no history.
It is not an idiom. Unkindness is often called heartlessness, and so the expression "have a heart" means "Do not be unkind."