If you want to do the ribbon pulling ceremony, make sure you consult
with your cake maker, who will most likely want to hide the charms
herself when she ices the cake. It is not
advised that you try to plant the charms yourself. The ribbon
pulling should occur before the cake is cut and can be announced
by your master of ceremonies.
If you like the idea of the ribbon pulling ceremony, but do not want to do it at the wedding, consider having a small cake made for your bridal luncheon/tea party and doing it then. Or, mention the idea to your maid of honor who may be willing to incorporate it into your bridal shower that way you can get a charm too!