Someones who's erected or soft penis is so large that one is said to be able to see it from space. This term can only be applied to people who have had their male reproductive organs compared to that of a horse. People defined as gargantuan hammers tend to be in prison or working as a prostitute. ( pronouns: dude, guy)
"Holy shit, Graham is a fucking gargantuan hammer"
A gargantuan spunk barrel is where a person swallows loads from multiple people in one sitting.
“Luke is a gargantuan spunk barrel, did you see how many loads he swallowed”