Husband and Wife agreed that whenever they want to have _ _ _, they will call it 'PHONE CALL' so that the children won't understand.

One day, Dad sends Son to tell Mom that he wants to make a 'PHONE CALL'.

Mom replies:
"Tell your Dad that the Network is busy today."

Dad replies:
"Tell your Mom that the call is urgent, if Network is busy, then am going to a PUBLIC PHONE BOOTH."

Mom replies:
"Tell him that if he dare goes to Public Phone Booth, I will OPEN a Business Center and all 'PHONE CALLS' will be FREE ...."