This chapter discusses unnatural sexual offence, a sexual intercourse against the order of nature, when the act does not involve penetration of a woman\'s vagina by the man\'s penis. Sodomy, tribadism/lesbianism, buccal coitus, and bestiality, are discussed in detail. Sodomy, seen among sailors, prisoners and in military barracks and prevails at all levels of society, is the anal intercourse between two males or between a male and a female. The presence of semen, feces, soft paraffin and pubic hair on clothes is almost diagnostic of sodomy. In lesbianism, the external genitalia may show scratch marks, or bite marks and it is usually indulged by women who have repulsion for men or who suffer from nymphomania. Buccal coitus denotes penile or vaginal oral sexual intercourse and can be performed by both males and females. The only material evidence of buccal coitus is the presence of spermatozoa in oral cavity of the fellator and buccal mucosal cells on the external genitalia of the subject.