Sheet Stuffing Tool

I printed mine in PLA-CF with 60% infill. A better choice would be ABS for higher strength, again with high degree of infill. At 6-8 inches from the apex of the corners of the mattress you may either insert the tool flat and fully and rotate it 90 degrees (either CW or CCW) or alternatively first lift the corner of the mattress manually and stick the tool in fully with the blade vertical as a simple wedge. The second approach reduces stress on the tool. Either way should work fine. I tried it both ways.