I was so inspired by Patricia's post on printing, that after mentioning it yesterday I immediately went into the studio to see if we had everything we needed to do the same.
I followed the instructions at Let's Explore and taped off a rectangle (and one for me, too). We just used our tabletop since it's very washable, but you could also use a placemat or cookie sheet. Maia painted in the rectangle, then drew designs in the paint with q-tips (her favorite part).
You're supposed to wipe off the taped edges before making the print and we did when patience allowed -- i.e. a couple of times. I think an easier way to get a clean rectangular print with the younger kids would be to place a cheap pre-cut mat (or cardstock with an opening) over the painting before pressing your paper down. Also, Maia used a lot of paint which got a little blotchy and obscured the drawing once the print was made. A roller might be a good way for a toddler or preschooler to produce a thinner or at least a more even layer of paint.
We both had fun doing these and will definitely try it again. As usual, our versions are a little more free-form. As Maia get's older I imagine her designs will be more identifiable, but for now I'm enjoying both the abstract art she produces most of the time as well as the more occasional person or skull that she draws.