The most memorable scenes start long before clothes are removed. Focus on the buildup of desire and the mental state of the characters.
Make the reader root for the character's emotional safety first—the romance will follow naturally.
A character in their late 20s or 30s has never had a relationship (not just sex). They feel like a freak. Then they meet someone who doesn't care about their "number."
Conversely, for the non-virgin partner in a relationship with a virgin, unique pressures emerge: fear of "corrupting" the other, anxiety about being a disappointing first, or the burden of having to "teach."