When an unrecognised caller rings your child, or one of their friends (who is on their Allow list) calls at an unsociable hour then instead of your child's phone ringing, your phone rings. When you pick up you hear the announcement:
“KidsLine - Connecting you after the beep, then press 1 to accept, hash to block or hang up for voicemail”
You are then connected to the caller. You can find out who they are and what they want, and then you have a number of options:
If you press 1 or * then both you and the caller will be put on hold, and trueCall will call your child. If you want you can hang up at this point, or you can stay on the line. When your child answers all three of you - the caller, your child, and yourself - are conferenced in together. You can introduce the caller to your child and stay on the line for as long as you like to check that everything is OK.
When you hang up the caller and your child can continue their call.