Tummy time isn't an exceptionally happy time in our house, and it's quite hard to do. I can't put her on the floor when Steven is awake, and I also have to watch for the dog. I also hate to put her down after she eats because she inevitably spits up on the play mat. However, we're working on getting more tummy time in because we need to work on those neck muscles!
Of course, Steven now finds the play mat quite fascinating and loves playing with the toys. Another good reason to not set her down when he's around!