How do you handle a wiggly, eight week French Bulldog?   You wear him out!   You then place worn out puppy on a soft, cozy blanket and wait until he crashes. Then start snapping away. 

But wait!   If you are compositing your pup into a digital background, note that you should definitely pay attention to the perspective and the angle at which it is shot. Not doing so will leave you pulling your proverbial hair out as you try to combine the two images together.   This is one case where a ounce of prevention is worth a pound of cure!  A little care goes a long way.   

There are many ways to extract an image in Photoshop.   The technique I used in this image involved the Pen Tool.   It is very powerful!  With a little practice, you can maneuver this tool like a pro.  In order to "sink" the puppy more comfortably and realistically in the image, I cut and pasted a bit of the background material, and warped it into place over the puppy's body and masked any areas I didn't like. 

The image was terrific when completed, but I used additional hand-painting, digital techniques to complete the finished image.   Enjoy!  The biggest challenge may be to find a subject as cute as Ziggy!