A childhood belief about prayers

I used to believe that prayers were like phoning God ie when you made the sign of the cross it was like dialling the number and after you said your prayer you HAD to do the sign of the cross to hang up or God would still be able to read your mind and he'd know if you were doing or thinking anything bad. I also believed that if you were interrupted during your prayer you would have to stop and make the sign of the cross to hang up and THEN you could attend to the interruption. I was about eight years old when I started to doubt this belief but then one day we were saying prayers in class (Catholic school) and the teacher made us do do sign of the cross but then another teacher came in and our teacher just stopped. My friend leaned over and whispered to me and said "Be good, God can still hear us because we didn't hang up". Thus my unusual belief was reaffirmed for another year.