2:40 in this video
The Floor Press is performed just like a Dumbbell Bench Press except you are lying on the ground instead of the bench.
To set up, sit on the floor with dumbbells standing on their "head" right next to you.
You will grab the dumbbells and lay back as you raise up to the start position of a bench press.
You'll notice that since you are laying on the ground, your range of motion will be shorter. This puts more of an emphasis on the triceps and takes pressure off of the shoulders.
Want to spice it up?
Wrap a band around your body and grab one end in each hand before you lay back with the dumbbells.
This will give you the added tension of the band along with the weight of the dumbbells that you're pressing.
With the decreased range of motion, you should be able to go a little heavier than a normal Dumbbell Bench Press.