I use swiss meringue buttercream.  Can you put a Rhinestone applique on the cake side with this buttercream?  Will it start to slide off as the buttercream comes to room temperature?

Also, where is the best place to buy these appliques?  I'm referring to the ones like in David Tutera line.  Thanks!

maybe your local fabric store -- they have them on amazon -- you might have to adhere them with toothpicks or something but beyond that they are not food safe for example you would not put them on your mashed potatoes kwim on the mp would be gross right so just a thought

i mean would be gorgeous on a cake where it's not touching the icing like on a plateau or within a floral arrangement or something like that mounted on a plaque or set into a separation between stacked cakes --

best to you

They probably won't slide off if you push them into the icing, but you'll need to put some kind of barrier between them and the cake because they're not meant to be used on food. If you cover the back with melted white chocolate, then let it set up a  little, then press it onto the cake so that it's good and stuck on there it should work unless the room the cake will be in is unnaturally hot. Personally. I wouldn't use those on cakes at all just because of the food safety issue.