Klingon mating rituals
From Memory Alpha, the free Star Trek reference
Klingon mating rituals are a series of courting traditions held by the Klingons. Klingon mating rituals include combative foreplay. (TNG: "The Emissary"; VOY: "Blood Fever") The ritual begins with each participant sniffing the other's right arm/hand. Then each grips the other's right hand as to cause bleeding.
Klingons traditionally mate for life, and it is not uncommon for them to take commitment oaths after only one encounter. (TNG: "The Emissary") While a full Klingon marriage ceremony involves many witnesses and an elaborate re-enactment of the Klingon creation myth, the much briefer oath of marriage requires no officiant or witnesses and is accepted legally and socially as constituting marriage by mutual consent. (TNG: "Reunion")
The mating ritual as described above is not always carried out when mating occurs between a Klingon and a member of another race, (DS9: "Penumbra") and it must be remembered that Klingons often do not like non-Klingons mating with members of their houses.
It is not uncommon to break multiple bones during Klingon amorous play. In fact, fracturing a clavicle on the wedding night is even considered a blessing on the marriage. Jadzia Dax describes the Klingon mating ritual as the participants "jumping on each other like a pair of crazed voles." While some, such as Dax, found this exciting, others, such as Quark, found it particularly intimidating. (DS9: "Looking for par'Mach in All the Wrong Places"; VOY: "Blood Fever") Speaking about Klingon courtship and marriage, Martok once noted that no one can be in control of who they fall in love with. (DS9: "You Are Cordially Invited")
Worf jokingly described Klingon mating to Wesley Crusher as involving the male reading love poetry while ducking the furniture thrown by the female. (TNG: "The Dauphin") Because of his traditional Klingon values, Worf, in general, took mating much more seriously than his partners did, much to his chagrin and theirs. (TNG: "The Emissary", "Hide and Q"; DS9: "Penumbra")
