There is a "shaping" technique where the top of the cake is bigger than the bottom.  Not completely "upside down", just bigger at the top.  I need to know how to do that.

just trimming the bottom of the cake, if is frozen will be easy 

that's what i thought, but figured i better get any details i can.  thanks!! :)

I've done this with several cakes. The easiest thing is to have your cake cold or frozen and stacked. If there is no filling other than buttercream, then you can stack with the icing. Place a cake board on top of the cake, then flip upside down and carve. It is easier to carve upside down and easier to see your angles. If you have a cake board that is the size of the bottom of the cake, then you can use that as a template to help keep your round shape at the bottom.

For example, if you need the top of the cake to be 8" and the bottom to be 6", place your 8" cake board on top of the cake, flip it upside down, and place your 6" board on the now top. Carve at an angle between the boards until you get the shape you want.  When done flip back over so the 8" is again your top. Hope this makes sense. Good luck!
 

great idea!  thanks for the help!

It's called tapering.

I found this I hope it helps, and I have another printed on paper that shows a better way to do this, Im trying to find that for you also:

http://www.wickedgoodies.net/2012/07/how-to-taper-cake-tiers/

Ok, Ive searched the net and cant find her pics online...but she sent them to me and I copied them...basically:

you bake 1- 8" and 2-7"

or you can bake 3- 8" cakes, these two are the best fit for them to cut/stack right

get your largest cake pan and put it on the table, this pan will catch all your crumbs and pieces as your cutting your cake to taper

place a NON SKID mat and a small pan on it to elevate the cake

cut your cake boards to: 1-5" and one 7" these boards will be placed as follows...one on top and one on the bottom of the cakes

now on the small cake pan that you have sitting in the large pan to catch pieces...place the 7" cake board and a cake on it, place another board on that cake, and then another cake so you should have board, cake, board, cake and now place the 5" board on the cakes. So your small board is the top board, and then you have cakes going down to the larger cake borad.

Using the boards as guides make sure the knife is always in contact with both boards, start cutting/slicing, from small board to large board...this gives the tapered look..

Then when your done slicing/craving/tapering...turn your cakes over and your tapered: LARGE TO SMALL...

Does this make sense? Im a visual person...so she emailed me a few yrs ago the instructions.