During my IR training, I was asked if I would accept SRAs on several occasions "for Controller training" - perfect timing for me and very good training for both parties. It's one of my favourite procedures - the Controllers do all the work and make all the calculations and I just follow their instructions!
I recall one who said so much, so quickly and so excitedly that he had to announce a break in transmission while he caught his breath and had a drink!
A good SRA is an art form so I'd imagine it's one of the tougher one for Controllers?