I have done stenciling on a cake board, on fondant (and a demo). I got the instructions from Nick Lodge's DVD French Toile cakes. After you place the stencil on the freshly applied fondant, you rub it in with a fondant smoother, so the fondant slightly comes up through the design holes and stays put. Then smear thickly with thick royal icing (I used black) over small 6-9" sections, and scape off excess with metal bench scraper in several directions, then do another section. The royal dries quickly on the stencil, but doesn't harm the effect, and most of it is scraped off during the process, leaving a thin film. If you miss a spot after removing the stencil, you can lightly move the stencil over the dried design, then it drops in the original raised royal pattern because it's slightly raised.

I like the crisco/oil smear idea on the back for a cake side. I have a tilting turntable, so this might be an occasion to use it (finally!). I have a black and white damask shoe box cake next week, and was thinking of doing panels like in Sharon Zambito's Boxes and Bows DVD, rather than covering it and then stenciling.

Ron Ben-Israel uses a lot of impression techniques, but does them on fondant bands around the cake sides, not directly on the fondant base. Maybe that's the way to go.
Sorry I wrote a novel, but nice to take a breather on a Monday

Sweeties,(my name is Kim also!) I have that same video. I used that technique for a toile cake and a planter for a cake show. I love the video because it shows you so much. I found that when Im trying to do it on the sides of the cake though, its kind hard to keep it still and press it in like he does. But if you can get someone to hold it for you while you stick pins into it, then you can do that technique and it works great!
But one thing you want to make sure is to pat dry your stencils because if your not careful, they can be damaged easily!

Thanks Kim! I was at your house for Jen Dontz flower class last fall! Remember me?

Oh yah! I didnt even know that was your screen name! Did anyone find your missing stuff?

No, I didn't expect to. At this point, I'd like to feel like an idiot and find them hidden in all my cake stuff somewhere than to lose them forever.

Thats a shame. I dont think Jen got her tweezers back either. No one claimed the pizza cutter or the smoother that was left. Who knows.
I saw Patricia and Stephanie at the cake show back in April.

i had a go with the damask stencil and quickly decided this is a technique i will be trying on dummies for a LONG TIME!! so difficult, and so messy and like the OP said, you need to be an octopus!

If you try using the pins on it and a little of cooking oil, it works really well.

A couple of tips I learned is not to roll out your fondant in cornstarch or ps as the royal icing doesn't stick - just use shortening. Be sure to clean your stencil every time. Someone pointed out that it is time consuming but it helps.

If you start with your royal icing in the center, it acts as a 'glue' to hold your stencil in place. I was even able to take my hand off for a second. When you smooth, start at the middle and go it 1 direction only. So, start in the middle and smooth to the left. Then start in the middle and smooth to the right. Never go back and forth so your icing doesn't lift up.

The first time I tried it, I wasn't feeling good and I had 4 cakes to do. I did practice a little and then went straight to the cakes - black royal on white icing. I could see my mistakes but everyone else thought they were flawless. Lucky me! LOL

The nice thing about cake-muggles is that WE see our mistakes, but they look at it and say "OMG!!!!!" God Bless Them!!!