Lyric discussion by 60_miles_an_hour 

Agreeing with everyone up their about it being about pure, animalistic, raw, intense passion or lust, sexual awakening etc.

I think it's further enunciated by these lines:

"Be careful of the curse that falls on young lovers Starts so soft and sweet and turns them into hunters

A man who's pure of heart and says his prayers by night May still become a wolf when the autumn moon is bright"

A new relationship may be nice and sweet and then suddenly bam, their want/lust for each other becomes so intense (i.e., the 'curse'). Likewise with the second part, a man who appears to be pure, innocent and religious, may still become overcome by passion and sexual desire for somebody (i.e, become the 'wolf', the animal inside him).

That's just my two cents. What a brilliant song it is!

An error occured.