[His watch pings, and there it is -- a chicken leg and a strawberry to greet him on his screen.]

Look. [He turns his wrist so that she can see her own handiwork, and offers an explanation afterwards.]

You can use them any way you like, though they're often implemented to denote a certain 'tone' to the conversation at hand. They're called emojis, but they're really little more than miniature icons.

Not to mention they're just amusing to see.