Heres a no mess way to spread icing on your cake without “pulling” the cake apart. I started using this tip, and I can tell you, if your using store bought icing (or even homemade) it makes it super easy to decorate.
First, take a round storage container and place a gallon size Ziploc bag, corner down first.
now just add your icing,
then pull the bag out, and all of the icing should be in one corner,
Then twist it and snip the corner off (not to much, smaller is better)