Book 1. What is first sex in our understanding? Is it funny to ask such a question? But, alas, not everyone knows what it is. The book step by step reveals sexual behavior (extragenital and genital forms of sex). The next step is intercourse—but it too hides many subtleties (autofellatio, cunnilingus, fellatio, anilingus, teabagging, etc.). You’ll definitely like the book.