... Because after a few bottles of Cherry Coke, a head injury, and bribing a goat named Vinny... I've got the research on the phrases you suggested! =P j/k So why hesitate - Here we go!

"Button your lip..." - submitted by badlydrawnstickman

Of all the phrases submitted, this was the hardest to track down. Actually, there isn't really much information about it anywhere. I couldn't even find a date around which it might have originated. It's like, it came out of nowhere. *spooky* =)

From what all I've read though in the past few days, it seems that it might have been an extension of the phrase "Hold your tongue." Somewhere along the way someone felt that holding one's tongue wouldn't be enough of a command to keep someone from spouting a secret, so they added on the very visually based phrase you see above. Because it was such a strong word picture, it caught on... and we still use it today.

Again, this was the one with the least information. I'm sorry badlydrawn... I guess some phrases just want to be kept secret. Kind of ironic that its meaning in itself is about keeping a secret. =)

"It Ain't Over Til the Fat Lady Sings..." - submitted by Ruuzu

This phrase was coined by Dan Cook, a broadcaster, in April of 1978 after a playoff game between the San Antonio Spurs and the Washington Bullets (now known as the Wizards). His original phrase was "The opera ain't over until the fat lady sings." It is a direct reference to what VOR pretty much said in their comment on the original phrase post. Most people's mental picture of an operas ending is of a large woman dressed up in Viking garb, hitting her highest note, and often the last nerve of those that have been dragged to the event. 
 
I stumbled upon who coined the phrase "It ain't over til it's over" while reading this information. You know who it was? Yogi Berra, a former New York Yankees catcher. What's even funnier is originally I thought that Yogi Berra was the cartoon bear with the sidekick named BooBoo. Hmm.... You sure you should be trusting my research? =P

Monkey Wrench - submitted by VOR

In 1903, a man named W.H. Sargent spoke of the slide that moves up and down in the handle of the tool in question and said that it resembled a toy monkey... hence, the name. But, after stating this in the magazine, "The Progressive Machinist", a man named H.E. Madden wrote in to correct him. He stated that the monkey wrench was actually invented by a man named Charles Moncky, who sold his patent for it for $2000.00. Throughout time, Moncky became Monkey.... and no one complained because well, frankly, it's a cute name for a tool. =)

"Monkey on/off your back..." - submitted by VOR

According to the Dictionary of American Slang this phrase, coined circa 1960, refers to drug addiction. It states, "When without drugs an addict feels weighted down and depressed, when buying drugs an addict is supporting pushers and his drug habit, thus, fig., the addict carries an extra burden;" Also, good to note, is that the size of the monkey refers to how serious of a drug addiction a person has. (Large monkey=very serious addiction, etc.)

Today, this phrase has expanded to generally mean any pressure we have weighing upon us, whether it be mental, physical, financial, or of a moral sort.

Thanks so much you guys for submitting those phrases! If anyone else has some they'd like me to research feel free to leave them in the comments. =) Hope you guys found this as interesting as I did.

I can't end this without a question, it's a hard habit to break. =P I'll ask a basic one. We've all heard this one before.... but not on thoughts.com!

If you could have any superhuman power... what would it be and why?