Supporting Billys Head

Billy and George were driving into Lame to watch a match when a tyre burst and they swerved into a tree. George was all right, but Billy, who hadn't been wearing his seatbelt, was flung out on the road and fractured his skull.
Distraught, George ran like the blazes to the nearest phone box and phoned for an ambulance.
'Is there anything I can do before you get here?' he asked the hospital.
'The best thing you can do is support Billy's head,' said the doctor.
Five minutes later the ambulance screeched to a halt at the scene of the accident and found Billy lying moaning in the road and George jumping up and down beside him shouting and clapping: 'Billy's head - rarara - Billy's head -rarara.'