For how long after full auto were you chuckling away to your self?

I remember when I was first told to use auto, we were all in a line for a download when we were given the order to 'Mexican Download'. We were all like 'Is this an Army thing?' (We were all RAF) so I had to ask what the hell a Mexican download was. He said 'Switch to auto', depress the trigger and when it stops I'll check it for clear. He really didn't want to take the ammo back!