Guy,
You yourself admit that it was something you have never tried before. Sex gets monotonous after some time unless you keep varying the position, setting etc. One great way yo have sex is at an odd time, may be during a lunch break or early in the morning where you can still rollback and go to sleep for a few hours. Many men are known to be early "risers" and are at their peak when the sun rises too.
The logic is simple. The body has had a good night's rest and is ready for action. Early morning sex is also a bit frenzied as there is not much time for those relaxed foreplay times. You have a day to catch up with and not a full night of sleep. This gives you an adrelain rush that you convert into great sex.
Often the sex moods of men and women do not coincide, as men have an erection as soon as they rise. Women are more ready for sex late at night. So do be gentle with your partner. She will not like an erection greeting her in the face as soon as she opens her eyes.
Morning sex has to be spontaneous. Planning in advance will spoil it all. It has to be spur of the moment. Do keep those condoms ready though. You dont want to hunt for them and spoil the mood. Morning sex can be a great way to start the day.