A pinger is generally a video game term. It might be used in the real world some time, but I don't know anything about that. A pinger is an attack that yields no success. It's name originates from an arrow that bounces off of a piece of armor, which usually makes a "ping" noise.
A paintball team decides to storm the "base" and steal the other team's flag. However, everyone on the invading team is taken out. The at-base team yells "pinger" at the losing team, smiting them with disgrace.
A tease on a dating site - someone who persistently sends cute or cryptic messages, but has no intention of meeting you - they are just testing the waters. Pinging you.
A pinger sends a message like this in the middle of the night: Having sweet dreams? Leaves you wondering - does he want to meet me? or is this what I can expect if I keep communicating with him? Cute, cryptic, ambiguous messages...