I have seen some videos where they do this on ficus.
Grafting is quite advanced, and easily understaken. In order to be successfull you either have to be a bit lucky, or better, have someone help you that has experience.
I have tried an a sacrificial Sakura about a week ago.
The buds where just about to burst and I assume the sap was flowing up the tree so I pegged a few and covered the join in cut paste to hold it
They appear to be beginning to bud at the moment but that may just be residual energy from the peg I placed. Hopefully they will take.
Its all good practice at the end of the day haha