onanism vs self-rape

onanism

noun
  • Masturbation. 

  • Ejaculating outside the vagina during intercourse; (the performing of) coitus interruptus. 

self-rape

noun
  • Masturbation. 

  • Masturbation without self-love. 

  • An act of rape where the rapist identifies with or is the same as the victim. 

  • Behaving contrary to one's own nature, usually as a result of outside pressure. 

  • The act of inflicting obscene violence against oneself. 

  • Self-destructive activity. 

  • Submission to an unwanted sexual act. 

verb
  • To engage in an act of self-rape. 

How often have the words onanism and self-rape occurred in a corpus of books? (source: Google Ngram Viewer )