The second part or section of Kama Sutra is titled 'On Sexual Union', consisting of ten chapters, devoted to the particulars of erotic love. Chapter 1 of the second part is named, 'Kinds of Sexual Union According to Dimensions, Force of Desire or Passion, Time'. Vatsayana delineates the various categories of men and women falling within the genus of erotic love, lust, passion and desire. Man is classed in diverse ways according to his measurement of lingam, corresponding to the woman's dissimilar measurement of yoni. Equal and unequal unions also exist, referred to by yet again separate stages.
Chapter 2 of the second section of Kama Sutra is titled 'On the Embrace', listing down variant ways of embracing. The said chapter on embraces is also titled 'Sixty-four' (Chatushshashti), owing to contributions of previous authors of Kama Shastra. Although Vatsayana portrays that the four kinds of embraces constitute primarily into man-woman sexual union. Embraces are divided into four heads, namely: Touching, Rubbing, Piercing and Pressing.
Chapter 3 of the second part of the epic love treatise, Kama Sutra, is named as 'On Kissing'. Guiding down one on the path of assorted sorts of kissing, Vatsayana speaks about the various types of kissing that a young lass is capable of. Though others view kissing in various perspectives, yet, Vatsayana states that a passionate kiss has no predetermined time while into the process of sexual mating. Opposite sexes can choose from the umpteen options of places of kissing in the body, as is explained by the author.
Chapter 4 of the second section, On Sexual Union has the header as 'On Pressing, Or Marking, or Scratching With the Nails'. Nails, scratching and biting occupies central position between two people while frenziedly and passionately in the process of love making. However, Vaysayana speaks that such kind of sensitive marks or pressings should only be made in cases of deep love and not just for the sake of doing it. The author also explicitly lays down specific times of the day when such pressing or marking with the nails can be made possible. According to Vatsayana, there are several classifications of nail scratches or marks while in copulation. Various kinds of loving stages also exists in this list together with their post-effects devoted to chapter 4.
Chapter 5 to Kama Sutra's second section on Sexual Union is titled as 'On Biting, and the Means to be Employed With Regard to Women of Different Countries'. Vatsayana states that all bodily places that can be kissed are also capable to be bitten while in zealous passion. In this context, kinds of healthy and harmful teeth necessary for biting are also listed in details. Biting, according to Vatsayana are of various kinds and stages, varying according to a man's love for a woman, who is further classified from different countries. The lower lip, the cheeks, the breasts, the shoulders are some of the bodily places capable of being bitten.
Chapter 6 to the second part of Kama Sutra, On Sexual Union is headed as, 'Of The Different Ways of Lying Down, and Various Kinds of Congress'. Vatsayana here tries to make one comprehend the positions obligatory for a woman and man before going into sexual union, or congress. Women, according to Vatsayana, must lie down below, with the man on top, listing down three primary congresses for women as high, equal and low. The different kinds of lying positions mentioned however need profound practice, made perfect only by masters.
Chapter 7 in part two of Kama Sutra, On Sexual Union is titled as, 'Of The Various Modes of Striking, and of The Sounds Appropriate to Them'. Sexual procreation between a man and a woman is personified by Vatsayana as two people engaged in an altercation, during which each one tries to outdo each other by performing the best. As such, enraged beatings or strikings while into the frenzy can be made in body parts of shoulders, head, space between the breasts, the back, the jaghana or middle part of the body and the sides. Striking is further divided into several sections, which induces pain. Hence, the woman while emitting impassioned sounds are also sub-divided into sections, like the Phut sound, the Phât sound, the Sût sound or, the Plât sound.
Chapter 8 in the second section of Kama Sutra, On Sexual Union is named as, 'About Women Acting the Part of A Man; and of A Man'. The present chapter states down distinctly two separate actions while into the sexual union. A woman, according to Vatsayana possesses stipulated deeds during this phase, as compared to a man, who also possesses stipulated deeds needed to work out. A woman is at times needed to perform like a man in phases of copulation, letting go of her bashfulness; in the same manner, a man is also ordained to make his beloved shed her coyness to be united.
Chapter 9 in Kama Sutra's second phase On Sexual Union, is headed as, 'Of the Auparishtaka or Mouth Congress'. The present chapter is dedicated to describing two kinds of eunuch class: those that are garbed as females and those garbed as males. Eunuchs clothed as females perform specific actions with their mouths, known to have derived pleasure out of it. This is precisely referred to as Auparishtaka. Eunuchs clothed as males engage themselves with other male counterparts, leading the life of a fantasising shampooer.
Chapter 10 of the second section grouped under Kama Sutra's On Sexual Union is titled as, 'Of The Way How To Begin and How to End The Congress; Different Kinds Of Congress And Love Quarrels'. This last chapter to the second section somewhat winds up the extensive Kama Sutra treatise on various kinds of pleasured unions. Vatsayana here states in detail the progressive stages that a man must utilise in order to culminate in copulation with his mistress. The loving congress comes in various kinds, which at times incorporates lovers' quarrel.