She didn’t say explicit sex scenes...just sex scenes. If I had to, I’d prefer writing scenes like you described...two people walking into a room and later walking out with a glow on their faces. Leave it to the readers imaginations.
It would depend on your plot. If you have characters who are a married couple who live together, it's kind of understood that they have sex, especially if there are children. You could easily have occasions when they go to bed together at night and smile affectionately at one another in the morning.
As a reader of both mystery novels and romances, I much prefer this to more detailed descriptions of what people are actually doing with their body parts. The romances I like are about people's falling in love and getting to the point of marriage, not about what they do once they're married.