I'm trying to front some dummies with butter cream, but since they don't have the weight the regular cake has, It won't stay in one place when I apply pressure. Any tips?

For the smaller sizes you could stick a large fork used for carving into the bottom and hold it in your hand while frosting. Best to have 3 or 4 prongs.

we used to have a heavy piece of wood with nails sticking up on it

it was kinda scary looking otherwise --had to be careful where you left it--

like not on a chair or anything

but it worked

Costumeczar did a blog post on that. Google "A Cake to Remember dummy cake tips", it should pop up.

I made a dummy decorator out of the following items all hot glued together in order from the bottom up: glass block, 3" PVC pipe section, 3 nails.  Set this on some non skid on your turntable and then impale your dummy on top.  If you don't like covering with the fondant hanging down, just impale a larger cake board on it first. Costs less than $10, available at the hardware store, no cutting or nailing, and it works great!

Ateco three pronged pivot...

http://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1272&bih=649&q=three-pronged+pivot&oq=three-pronged+pivot&gs_l=img.3...5702.19397.0.21452.19.17.0.2.0.0.389.1645.12j4j0j1.17.0...0.0...1ac.2j1.11bHjZTMUbA#hl=en&tbo=d&site=imghp&tbm=isch&sa=1&q=ateco+three-pronged+pivot&oq=ateco+three-pronged+pivot&gs_l=img.12...43952.57223.2.59760.20.20.0.0.0.0.106.991.19j1.20.0...0.0...1c.1.ydZGa5s8AvU&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.41642243,d.b2I&fp=5e6594a945d89275&biw=1272&bih=649
 

Here, I found it. I'm super cheap so this is my solution: http://acaketorememberva.blogspot.com/2012/03/diy-cake-dummy-decorating-board.html

Thank you all for your help.

The Ateco solution for $30 was the best for me. I just ordered online, and I own a cake bussines so i will get the cost worth over time.

I'll keep you posted on the results.