For the love, comes the burning young
From the liver, sweating through your tongue
He notes in the first line here that youth are so enthusiastic to find love, but fire only lasts until the fuel is out.
From the liver sweating through your tongue'
means that her words are no longer coming from her heart, but they are digested and filtered (the livers function is to filter, aid digeststion, and maintain equilibrium in the body; it is equally as important as the human heart). To me this remarks that in order to maintain a relationship, one cannot always speak from their heart, but filter their feelings so neither partner is hurt.
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