This idea has been around for awhile, though I have never done it myself.
Need:
Bath / pool
Couple of flash lights
Milk
Flowers / or objects of your choice.
Fill the bath with enough water for your head to submerge when lay down.
Regarding the flowers, I used real flowers purchased from the local shop. I had read that some fake flowers sink and did not have the time to start experimenting. But also think real flowers give a far more nicer effect with less editing.
Cut the heads of the flowers off and place them after your model has got into the bath.
Finally add the milk, you don't need much so would advise a little bit at a time until you reach your desired look.
Once your happy with the arrangement, start shooting!
Camera: Canon7D Lens: Canon 16-35mm