2.When someone tries to diss you (or say you will mess up on something ) and they either fail or are wrong, you slap the back of their neck. (Or vice versa )
3.When someone violates or rejects you successfully, you then slap the back of your own neck.
2. "I told Carlos he would miss his 3-pointer and when he didn't , he gave me the neck."
3. "After Tom was rejected by Sally, he gave himself the neck."