plip vs plop

plip

verb
  • To make the sound of liquid hitting a hard surface. 

  • To lock or unlock using a remote control locking device. 

noun
  • A light sound or action like liquid hitting a surface. 

plop

verb
  • To make the sound of an object dropping into a body of liquid. 

  • To defecate. 

  • To land heavily or loosely. 

intj
  • Indicating the sound of something plopping. 

noun
  • A sound or action like liquid hitting a hard surface, or an object falling into a body of water. 

  • Excrement. 

How often have the words plip and plop occurred in a corpus of books? (source: Google Ngram Viewer )