scissoring vs tribadism

scissoring

noun
  • A sex act in which two women intertwine their legs and rub their vulvas against each other. 

  • An act or instance of cutting (removing) with or as if with scissors, especially an act of cutting and censoring a film. 

tribadism

noun
  • Specifically, a form of lesbian intercourse involving the rubbing together of two partners' vulvae. 

  • Lesbianism. 

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