Thank you! And yes, I think this was very necessary for Draco and Harry. Without it, they would have been on edge more than is good for them in the final confrontation.

Poor Harry; he's so afraid of hurting Draco. But that's exactly what Draco doesn't need at the moment. He wants to go further, wants to push his own boundaries, because he thinks some of those boundaries were artificially established by Daphne. And yes, he wanted to show Harry that his body desired this.