Just like with any kind of story, there are many readers who enjoy immersing themselves into a character’s experiences, and for that kind of reader fine details can be very important. Especially when the pleasure derived from said experience hinges almost entirely upon its inclusion. If you are glossing over the entire intimate act you can probably skip it. But in erotica, the intimate details are part of the point in most cases.
Just like with any kind of story, there are many readers who enjoy immersing themselves into a character’s experiences, and for that kind of reader fine details can be very important. Especially when the pleasure derived from said experience hinges almost entirely upon its inclusion. If you are glossing over the entire intimate act you can probably skip it. But in erotica, the intimate details are part of the point in most cases.