Disturbing Was The Point...
I'm not usually a prude or anything, but for some reason I found the sex scene in this episode to be a little disturbing and twisted. I did find it cool how they continued to go at it while the entire building collapsed around them, but other than that...erm...
Maybe I should rewatch that episode soon, see if my opinion has changed...
I think the whole point of the "bringing the house down" scene was to illustrate the fact that, at that moment in her life, the last thing Buffy wanted, and perhaps needed, was another sweet, romantic love affair. For the first time, the Slayer needed pure raw passion to bring her back to life, and, just maybe to transfer the hate she felt toward her friends for bringing her back into a bright, noisy life, and there was certainly no one more capable of providing it than Spike. Certainly and without any doubt he loved her, but the only way he had of expressing that love was with a raw, rough, animalistic coupling. Remember, William grew up in a time when gentlemen and ladies had no sexual experience before marriage (granted, there were professionals available, but William the Poet would have been the type of man who would not avail himself of such base activities.) Almost certainly, Spike's only sexual experience was with Drusilla, with the possibility of Darla and Angelus tossed into the mix on occasion. He simply had no idea what romantic love was, so he gave Buffy exactly what she needed at that time: escape from the responsibilities and pain of the real world.
Arguably, an ensouled Spike the next season was a completely different vampire, but that is not part of the discussion here (neither is the subject of this post, really, but I'm not the one who was disturbed by the scene. This is only my attempt to give my view of it.)
