look up any word, like cleveland steamer:
 
8.
when your magic stick is at max travel in your partners anatomy
i usually prefer to be balls-deep bout three times a day....only a sufer knows the feeling
by Big BNP January 29, 2004
 
9.
To thrust one's penis into a women's vagina to a point where pushing the balls in wouldn't make much
of a difference or.... all worth while.
Women: "Ohh, Deeper, Deeper, Harder, Harder!"
Man: "I can't bitch! Im Balls Deep already!!"
by Tommeh Arris January 09, 2009
 
10.
Inserting penis far enough into vaginal canal that the testicles push against the outside of the females body.
While peering through a window Josva exlaimed; "John is definitely balls deep in Mel right now!"
by idon'tusecondoms December 04, 2007
 
11.
Verb - To take a risk for a potential reward
I went balls deep trying to bone my hot neighbor.
by KorinthianJailer May 02, 2011
 
12.
The act of sheathing one's cock to the hilt into another's orifice of preference.
"My best friend's wife squealed with pleasure as I sank my man-stalk balls deep in her pink starfish."
by Sweltering Satchel April 29, 2008
 
13.
Metaphor: the events of being deeply involved with something, this could be your homework; or something which has nothing to do with testicles or the length of orifices.
a. hey man what's happening?
b. im balls deep in my homework right now

a. that party last week was nuts
b. yeah! it was balls deep!

a. hear about that volcano eruption?
b. yeah it totally wreecked my neighborhood
c. eh, I was balls deep in the lava
by HappyDickFarting May 23, 2010
 
14.
In the literal sense, this means to insert the penis in its entirety into a females vagina, leaving nothing but your balls outside of said vagina.

It can also be used to imply that the action or event was taken to its extreme, with no other possible courses of actions available.
Joe: "Dude I came back to my controller and you were balls deep up in my ass."

Me: "Ahahahahahaha!" *accidently walks off cliff on map Jungle in Black Ops

Person 1: "Dude, we're balls deep in the Middle East now that Obama's president."

Person 2: "Not as deep as I was in your mom last night."

Person 1: "WTF?!"
by The One Who Sees... June 21, 2011