Shrek and Fiona are on their honeymoon and are doing all the newleywed things like making out on the beach and relaxing in a jacuzzi. It comes right at the beginning of the film mainly to remind everyone just how much in love the two ogres are and to set up that love to be tested as the movie unfolds.
This is a pretty cute dating montage. It has all the typical dating montage imagery, but slightly twisted because it's two ogres and not two people. Also, it is probably the only dating montage to actually contain flatulence.
