The first chenille baby blankets were made from flannel because it frays well. You lay your backing fabric down, smooth out your batt on top, then you lay 4 layers of flannel on top. The flannel against the batt is NEVER cut. You stitch lines on the bias every 1/2 inch across the whole the quilt top. After the whole top is stitched you cut through 3 of the layers right down the center of the lines. Some use a chenille cutter but I use my spring scissors being careful not to cut the last layer. Once all your chenille is cut, you bind the edge and throw the blanket in the wash to start the chenille process. It makes a ton of lint so check the lint trap regularly. It will also make lint in the dryer. It makes a lovely fluffy soft blanket.
There are several variations on this technique if you YouTube you should find tutorials.