look up any word, like the eiffel tower:
 
1.
NOUN : A male with 3 testicles instead of 2.

NOUN (2) : The third testicle in such a position.

NOUN (3) : Slang for extraterrestrial.
Extratesticles are normal people like you and I. You would never know someone was an extratesticle if you saw them walking down the street.
by ECHOSIDE March 31, 2005