I personally think that it is more difficult to write a sex scene because a death scene requires mainly for it to be believable/realistic to produce the right emotions. From car crashes to gun fights to heart attacks, the scene requires action and emotions that cause the reader to feel excitement and dread at the same time.
While a sex scene requires to be both realistic and to not sound “cheesy”. A sex scene needs to feel intimate and sexual. Sex is awkward, yes. But it should be written with words one would use during their own real sexual encounters. Be as vulgar as possible or as subtle as the characters personalities portray. The reader needs to be able to sense the high intensely of that first kiss to the last breathless moan.
Is sex an important part of the relationship?
This is an important question that needs to be answered for the development of the characters and the story as a whole. It could be possible that the actual sex scene in itself may not be as important as the act. It may therefore, have a greater impact in one’s story to perhaps lead into a sex scene but then never actually go into great details. But rather, let the fade and let a new scene take over.
On the other hand, the death scene is seen more often as the more important moment in plot development in most stories types. Characters are important. No one has experienced death before. Sex is a natural thing like breathing. Death is the opposite, not breathing. Need to bring out all of the right emotions. You can write around a sex scene. But if you wrote around someone’s death, you lose the important aspects of that person. How did they die, what did they die for, etc.
How do you foreshadow death?
Both are difficult to write and need to stray away from the clichés. I find that the most important aspect here is word choice. Word choice, in itself is also very difficult to decide. There is for example, the need and respect of publicly correct terms.
Also, to create a good sex or death scene the buildup in both must be very powerful, meaning, etc. Both are equally important aspects of character and plot development and therefore must be presented in such a way. For great examples of these, I have found that one should, (part from books), read about them in plays and movie scripts.
