Has little to no relation to one would actually think it means. In reality it is a term used when one is excited but doesn't know how to express their excitement. Commonly used as a fill in for "hooray" or "yes!"
You have just been awarded sexiest human being ever, what do you have to say for yourself?
"Start the Reactor!"
"Start the Reactor!"
by C-Wild February 19, 2009
Breasts that slant towards each side with large brown nipples that talk to you when you suck on them. They are considered highly hallucinogenic and can cause you to think you're part of a conspiracy on Mars.
As i began to peer down her shirt noticed the possiblity that Jen might have "start the reactor titties."
by dogbert12 May 30, 2011