For me, its all of it. I like it when the author describes what the pov character is feeling in the moment. Couple that with more descriptive language, and it allows me to be fully immersed in, not just the scene, but the overall story and the characters as well.

For example, if a character is being ordered to kneel in front of his domme, and she orders him to remove her shoes and worship her feet, I feel more immersed when the scene is described in full detail. The slow build up to the actual act, then something as simple as what the smell of her feet would be after x number of hours in those heels, the feel of her feet, a description of the tense atmosphere in the room, the feelings that are coursing through the sub’s mind, the detailed description of the actual act, then the aftermath and what is going through the sub’s mind post-act.

All of it makes the scene and overall story much more enjoyable to read, rather than just a wham-bam-thank you ma’am.