I am making a flip flop cake and each flip flop is on it's own board cut to the size of the flop and then placed on another fancy foiled board. I want them to stay in place on the main board, but everytime I move it they slide. I'm concerned about transporting it, too. I'm afraid they are going to slide into the side of the box. How do I keep the flip flops from sliding around?

You can put a smear of BC or RI under the individual boards thus adhering them to the main board. That should pretty much do the trick. Let them set for a few minutes before making any attempts to move the main board. HTH.

Measure and and scrape or sharpen to a point two wooden dowels or even skewers and put in each flip flop that goes all the way to the bottom cakeboard. It will anchor them. HTH!

Trevie is right (regular pencil sharpener works great for that). Dowels are great and stronger, skewers tend to shard off little sharp pieces of wood.
Also when you have time (for the next cake). Go to Lowes (or your favorite home improvement store) and buy double sided carpet tape. You will never ever have that problem again...no need to wait for something to dry. Plus if you (or client) needs to separate the hidden cake board from the decorative they can without having a messy bottom cake board to deal with.

Ok, I smeared the buttercream underneath each board and that definitely helped. I think I may stick some skewers through them, too, just to be on the safe side!

Thank you both!

How ingenious, wrightway777! I'll be at Lowe's tomorrow and will be picking up some double sided tape! Thanks for the tip! I never thought to use a pencil sharpener for the dowels either. You are full of great ideas! Thanks!

No problem...I'm always looking to double purpose things. PM me if you ever have a question like the above.
Heres another good idea: I love to take a stroll throughout the Home improvement stores and go through every isle in the craft stores (once every two months). You never know what you will find. My latest treasure (found at Michaels) are full alphabet and numbers in a victorian style concrete stamps. I'm going to use them as "impression characters" (perfect for monogramming fondant name plaques or tags) with my 40% off coupon I paid less than $4 for the whole set! I know its crazy!!! I'm going to post this latest find as a new post for everyone to see.

Ahhh..the beloved 40% off coupon...I don't purchase anything unless I have it! That was a great find. I noticed that you are in GA. Where at?

approx two hours south of Atlanta