[Neoguri]

Both morning or night are fine for me.
Most of the time, I prefer night sex as you can hug/talk/kiss then drift to sleep in each other's arms.
But it is important not to drift into sleep right after orgasm. - it leaves a bad taste emotionally that you don't care about your partner after the deed where she is still at an emotional high.

Morning sex is also very nice as you are more unlikely to sleep after the deed and that is a great help in starting the day with love and satisfaction.