How to issue a CPFP? I was reading about CPFP (child pays for parents) recently and I didn't completely get the concept of it.

Can someone please give me a brief explanation of how it should be done and what are the wallets that currently support it?

Is my understanding of CPFP even correct? A user sends a transaction to another, which is not confirmed, that user can send another transaction that is "connected" to it with a high fee, that when a miner mines it, they are forced to mine the first, unconfirmed transaction?
From the glossary:


  Selecting transactions for mining not just based on their fees but
  also based on the fees of their ancestors (parents) and descendants
  (children).


Thus, we understand that this is a policy that is implemented by a miner.
Now, the way we can ensure that our stuck transaction falls under this policy is by ensuring our stuck_tx has a child_tx with good fees.

For creating a child raw transaction, we just need the txid from the stuck transaction and new address to send it. Put the funds, the change, what's left is the fee. Sign it and broadcast it.

To determine the right fee and more details check this fee bumping page on bitcoin wiki.