Lyric discussion by mrmacphisto 

If you want verification read Willie Williams blog during the U2360 tour. Willie is the producer and light designer for U2's concerts and this is his favorite song. As one other person noted, and correctly so, it is a song about oral sex in an inverted position. Refer to the first verse: Figure of eight Six and nine again

In fact, from the same blog post, the original title of the song was soixante-neuf(French gives it a little more decorum).

@mrmacphisto What's oral sex in an inverted position. Normal position?

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