look up any word, like bae:
 
1.
A slang term used by heroin addicts that refers to the first time using heroin.
Son, you are a big boy and you are going to do what you want, but trust me, don't step into the big bang.
by playback July 21, 2008
 
2.
something that may have happened many billions of years ago, and was supposedly how the universe came to be.It is just a theory..
the big bang started the universe
by foozicle December 09, 2007
 
3.
Similar to docking and can be simultaneously be done in the act of docking,

The Big Bang is the act of pressing two penises together head to head, masturbating, and producing a massive explosion of cum comparative only to the creation of the universe.
"Johnny and Richard have a habit of creating The Big Bang every time they masturbate together."
by thunderdome May 07, 2008