1) Fun. Pings can be used for many things, one of which would be for fun. For instance, if you wanted to entertain yourself, you could send a ping in the form of an impact feeling at someone.
2) Primitive Communication. Pings, while very simple, are quite capable of sending small one thought communications.
3) Greetings/Expressions. Popular amongst natural psychics, now you can be "in." Pings are excellent for "let 'em know you're here" things. They are also very effective shows of expressions, such as the infamous "middle finger."
The most common and simple way to ping a person is thinking at them. This is a very simple process. The first step is acquiring the target (III A). The second step is thinking while directing your thoughts at this person. One method of this is sub-vocalization. Sub-vocalization is thinking with the intent to speak, or thinking JUST below the vocal level. To send a simple ping, one would simply think a concept at a person.
In order to add strength to a ping, it is common to send a burst of energy towards the target at the same time as the ping.
Another variation of a ping is a use of the infamous Psi-Ball. This is be done by formulating a psi-ball with a particular concept, and then sending it towards the topic.