True Story From The Marine Corps Recruit Depot - San Diego
We see Recruit Sykes stand at attention and slap the flat board outside of the DI hut
Recruit Sykes: This recruit requests permission to speak to the drill instructor.
DI: Speak Maggot
Recruit Sykes: This recruit requests permission to make a head call, sir.
DI: Is it and emergency head call Maggot?
Recruit Sykes: Yes sir.
DI: Then sound your siren and go
We see Recruit Sykes run to the head making the sound of a siren as he goes