There comes a time in a story when the characters will fall into bed with each other. Be it the Princess that has finally found her Prince and is ready for the Happily Ever After, the traumatic but necessary rape/plot device, or simply the Hero finally managing to convince the voluptuous Amazon warrior that he is worth a tumble in bed.
There are different ways to write a sex scene. From the succinct "They made love" to the long winded 3 page description of every move and feeling. I'm not saying one is better than the other, they fit their purposes.
With the first there is not much that can go wrong, except feeling that you wanted more. But you can always fill in the rest with your imagination.
With the more verbose kind it is easy to mess things up. The problem lies on trying to describe the body parts. With mouth, hands, neck, feet, legs or thighs everything is fine. Breasts are no problem at all. But as we reach the point where the intimate parts are involved things get confusing.
There seems to be no proper way to designate the bits involved. Even with the amount of names available to describe both male and female anatomy, there seems to never be a right one. They are either to clinical or too crude. Female parts are often referred to as mounds, folds, that place between her legs or the vague "inside". Male bits can have the very proper name of Phallus, manhood, member, or a string of euphemisms relying on long, thin objects for imagery. But lets face it, neither of the first three are very arousing. So many resort to euphemisms, which is not bad. It's just the choice of euphemism that will cause problems. And here is where my complaint lies.
I realize there is a reason someone might call it a spear. It's long, it's used in thrusting movements. But, specially in Fantasy, it does mean something else (you know, the actual weapon). In my first encounter with this particular euphemism I didn't realize there was sex involved. I literally thought the poor girl was being speared to death. When she simply went mad after that I thought it wasn't that bad, after all she was alive. Maybe that's why I cringe every time someone calls it a spear. Or a sword.
So please, I ask, keep away from weapon euphemisms when writing sex scenes, specially if said weapon is used for something else (i.e. Killing people). Or if you do, please make sure the reader is aware there is going to be sex involved, lest they be scared for life.