There are a couple of versions of this trick around but this is the best. The instructions are well written and the wax is just right not to soft or too hard.

However, there is one warning! Make sure that you have permission from the proprietor before you do the trick. Sometimes the wax can leave a bit of residue on the ceiling which can collect dust over a period of time so you end up with black marks. Also when the ceiling is repainted often the paint won't paint on top of the wax. As A result it can make you very unpopular, Believe me it's happens.

However, it doesn't always leave a mark and it won't matter it you only do it once or twice somewhere but if you want to do it as a regular feature somewhere, then beware. Otherwise a wonder full trick.