The title is a sexual play on words. The lyrics describe a cocktail ball, but there is obviously a double meaning.
AC/DC takes the music much more seriously than the lyrics to most of their songs. They often rattle off humorous lyrics so as not to be taken too seriously. Chuck Berry is a major influence on their lyrical style. He wrote many songs with highly suggestive lyrics, but presented them in a comical way so they did not seem offensive (see "My Ding-a-Ling").
Radio stations sometimes play the song together with "Rocker" because it's right after this on the album and the song starts up right away. Radio DJs just let the next song play since both the songs are short.
Suggestion credit: Nick - Paramus, NJ
An AC/DC tribute band from Norway and another from Texas are called Big Balls.