I heard that E-40 makes every one of his slang words up by squinting into his alphabet soup. He only got Flamboastin cause he choked on his soup and b'ler had to hiemlich him.. coughed that shit straight back into the bowl to reveal a word similar to 'flamboastin'. See he gotta squint or else the word would make NO SENSE whatsoever.
you can clearly see he gives props to the soup on the Game Related cover.
see, he's starin straight into that shit for inspiration.