Commonly, Pudd can be seen on a male or females face after a penis emits the liquid from it pee-hole.
However, it can also consist of any other substance that fits the bill. for instance, if one was to get mayo on their face from eating a sandwich or vanilla pudding after trying to eat a cup of pudding with no spoon. in this sense it is commonly used to make a double entendre.
One further use is if there is a residue left over from the use of illegal narcotics on one's nose or facial area.
Bonus points are always given when Pudd lands in the "Puddee's eyes, nose or hair or facial hair etc.