Which side is the handle of a cup?
If a cup has decoration that does not go all around, it is
usually oriented so that it will be facing a right-handed person
when they are holding the cup, with the handle on the right as seen
from the position of the user.
Obviously, however, a cup can be used by either hand, and the
question of what side the handle occupies is moot, unless this is a
trick question and you wanted the answer "outside."