The act of two guys engaging in a masturbatory battle, inside a dome-shaped jungle gym, where the winner is the combatant who can climax first. (Note: During the battle, the jungle gym should be covered by the wagering spectators to prevent any random onlookers from seeing inside.)
Term references the film Mad Max Beyond Thunderdome's arena where opponents battle each other to the death.
"Make sure there's no kids around! Bob and Bill are going beyond thunderbone! Two men enter, one man leaves!"
When some resigns or retires from a job, they are on "eternity leave". This can also refer to someone who has passed away, especially someone who worked somewhere for a long time, retired/resigned, then passed away later.
Oh I'm sorry, you didn't know that Kelly is on eternity leave? She resigned and moved to Hawaii!
With regrets I would like to inform you that my boss is officially on eternity leave. I will never see or hear them again. Ever.
The hypothetical man (often a sinistercharacter who decided not to go to boot camp) that is doing your girlfriend/wife while you are on deployment overseas.
Ain't no use in goin home,
Jody's got your girl and gone.
Ain't no use in goin back,
Jody's got your Cadillac,
Ain't no use in feeling blue,
Jody's took your checkbook too.