Mmm!
Severe turbulance means the A/C is temporalily out of control.
Standby well yes, will be followed very shortly by a jet upset.
That means mayday if you can get the words out with a mouth full of cockpit clutter.
ATC if an a/c is screaming for descent due severe turbulance he/she means it, it is just a matter of timing before the mayday. Severe turbulance can be the most frightning thing a pilot experiences in his/her career, he/she is NOT a wimp. Those who think he/she is, have never been in severe turbulance.
Mother nature is bigger stronger than any human built machine or person, luckily it does not happen that often.
