Well, the last reason is a logical segue for this subject, and yeah, it was inevitable that it was going to show up. Klingon sex is really violent pain sticks, bite marks, fractures and contusions you don't walk away from a Klingon tryst. No, I mean it: you're probably crippled or something. Just look at all the episodes with characters that have had relationships with a Klingon partner: Worf winds up with a slight cut on his forehead, but Jadzia Dax dislocated her shoulder. Little Quark ended up in sickbay for a day while he had his earlobe stitched back together while his Klingon lover looks on with a tiny trickle of blood on her lip. Sex isn't supposed to be about hurting the other partner it's an intimate moment of trust and sharing where you don't have to be afraid to show your vulnerable side. Klingons don't have a vulnerable side, and if they do, it's protected by six inches of body armour.