No Thompson, it isn't a 'tut tut' sound. It's a long, drawn-out rattling noise. You put your tongue firmly behind your upper front teeth and suck hard for ages. My sisters-in-law fall about laughing at my feeble attempts. It's a standing joke there. I always get asked to try and they always scream with laughter. I suspect it's to with their slightly different lips and mouth to my European features.
Do people still do the pointing index finger to side of head and wiggling it to indicate "He's a bit bonkers"?
I quite like the new thing where you put up the palm of your hand saying, "Talk to the hand, the face ain't listening!' That's really funny.