Okay, technically there's no sex in this book. Macabéa is a virgin, and every time she dreams about sex, she feels so "guilty" (3.81) that she "mechanically [recites] three Hail Marys" in an effort to absolve herself.
But characters do mention sex occasionally, and Olímpico, Macabéa's temporary boyfriend, is apparently some sex god who has done it with lots of women and thus has children sprinkled throughout Northeastern Brazil and Rio de Janeiro. Ironically, when Olímpico dates Macabéa, there is no hint of sex whatsoever. But not with Glória. When he starts dating Gloria, he "attacks [her] with the ferociousness of a male bee, craving for her honey and that succulent flesh" (4.322).