on thin ice vs ticklish

on thin ice

adv
  • dangerously, hazardously, delicately 

prep
  • In a dangerous, hazardous, or delicate situation; at risk. 

ticklish

adj
  • Sensitive or susceptible to being tickled. 

  • Touchy, sensitive, or delicate. 

How often have the words on thin ice and ticklish occurred in a corpus of books? (source: Google Ngram Viewer )