lay it on with a trowel vs soft-soap

lay it on with a trowel

soft-soap

verb

  • To attempt to persuade by flattery or pleasing words; to butter up. 

noun

  • Persuasion by means of flattery or pleasing words. 

How often have the words lay it on with a trowel and soft-soap occurred in a corpus of books? (source: Google Ngram Viewer )