Put on some old clothes you don't want anymore. The tighter the better.
Get someone (my wife in my case) to completely wrap you in duct tape from ankles to neck.
Be prepared to be made fun of and possibly have a panic attack.
Cut off the clothes with scissors in one big long cut (if possible).
Tape up the incision on your weird duct tape skin suit.
Fill the suit with expanding foam. I put 4 ft. wood dowels through the legs for support (they run from the ankles up into the body).
I used almost two rolls of tape. Home Depot sells decent size rolls for about $3. It's not the best but it doesn't matter. The most expensive part is the foam. I think I used about six cans at $5 a piece. There may be a cheaper alternative. Now, I know what people are thinking, "but you can just buy a store mannequin for about $100." That's true, but this thing is my exact build/size, and you can make it any pose you want very easily. It's very rigid and seems to be working fine. Time will tell how it holds up.