AAAAAAAAAAARRRRRRRRRRRRRRHHHHHHHHHHHH my kitchen needs a crime scene DO NOT ENTER sign on it,
1st after months of trying to find the perfect devils food cake recipe ( like Betty Crocker packet mix) i finally found one and the taste is perfect BUT!!!!!! my cake over rose and spilled out all over my oven.
2nd my designer stencil came so i covered a dummy yesterday in fondant soooooo excited to try this stencil today, 6 times iv tried and every time something goes wrong, e.g. cake moves, icing went under stencil, etc etc i did practice on a flat surface covered in parchment 1st and looked great UNFORTUNATLY my dummie cake dont wanna work. now i have 2 weeks till my brothers wedding which im making the cake for, iv had no training and im cracking up ha give me a kids character cake over a wedding anyday................... rant over ha

I've started lining the bottom of my oven with foil when I bake. It saves me the trouble of cleaning it when I have this happen. It doesn't happen often but it does happen. I've never tried to stencil on a cake so I can't offer any advise there.

Good luck with the wedding cake. I'm sure it's going to be lovely.

I recently did a stencil cake (in my pics) and believe you me I know your frustration.

This is what I did for my cake. Hopefully, it will help you out if you arent already doing the same process.

I didnt cover my dummy cake with fondant though, but instead I covered it with a long strip of Saran Wrap and then taped down the ends (top and bottom parts of the dummy cake). This worked really well for me, because I could just wipe off the royal icing to get a clean surface to pratice again, or just washed it off, or even after a few times I just removed the plastic and put more on. I use a small bench scraper to apply the RI, but didnt press too hard. I just gently smoothed it over the stencil and then gently went back over the design again to remove the excess RI. I used a medium consistency RI, because I found that if it was too thin it would seep under my design and mess everything up.

Also, on the stencil should be a hole. When you place the stencil up against the dummy cake side put a small pin (like a sewing pin) in the hole to hold the one side in place. That allows you to use one hand to hold the opposite end of the stencil, and then the other to apply the RI. I also used a pin with my real cake and it only left a tiny hold, and after just giving it a little rub it was barely noticeable. I let my fondant sit overnight before I applied my stencil so Id have a firmer surface to work with.

You could use some double sided tape or a small piece of the rubber shelf liner material between the counter and the dummy to keep it from moving.

Hope this helps.

I'm glad I was able to help. If you have any other questions do not hesitate to ask.