Wonderful start! I'm caught up and waiting for more.

I understand your concerns. I have been writing for years and the sex scenes are still the most tricky. How much is enough? How much is too much? When do you begin to border on tedious, redundant or comical? It can be a fine line but if you keep it true to your plot and characters it will be fine. Besides, can Spike and Xander ever have bad sex? Nah!