How do you go about filling in your props body's???

i have seen a number of ways. the stuffed trash bags with tape over them to try and control the "lumpy"ness.

people have started using chicken wire more and more. they wrap is around the PVC structure and use it to shape what the body would look like. Its cheap, and easy to manipulate. But be careful it can be sharp, use gloves and watch your eyes. I have even seen some people use the expanding foam over the chicken wire to give it texture.

I have used some strapping some times if i'm trying to do a quick figure. I use something called plumbers tape. It actually a fairly stiff strip of steel with holes every half inch or so. You can use it to make a support structure and screw through the holes to the PVC and then drape the cloth or clothing over it.

there are also the tape mannequins. You have a friendly assistant and wrap them in tape (duct or packing) with something under so that it doesn't stick to their skin. Then you cut the tape off in a straight lines up the back. Remove the cast from your model and reattach the seam. the tape tends to hold it figure (it may take a couple layers). Then the mannequin is used as the shape for the character. Some have used the packing tape method and with the right lighting get a very creepy partially visible ghost effect without any coverings.

For bubble wrap, use strips as wide as the length of the limb you are working on. Using packing tape, attach one end of the bubble wrap strip to keep it in place on the limb. Start wrapping the bubble wrap around and around the limb until you get the desired bulk. Secure it with more tape. You can also use the tape to shape the roll you have created to give it a more realistic shape.

For the torso you can also use hardware cloth. It is a stiffer version of chicken wire. As stated, use caution. When you cut it, the edges are sharp and they will cut you. I have found sealing the cut edges with duct tape is a big help. I typically use small nylon wire ties to join the pieces of hardware cloth together. Once it is all competed you can skin the torso with duct tape to help with shaping and to again cover any rough edges.