Mine have all trained ME. Tsam knows that if he knocks around 6pm, he can come out. Frank will sit and stare at me pointedly until I notice, and then he can have his run around (so long as Tsam's not out). Mocha does the same thing. Jacques will sit in front of the morio box and stare at me until I come and get worms out.
I've trained them all how to use the dragon slope - a carpeted wooden plank with a wire mesh tunnel and a metal grip to stop it falling off the door - to get in and out.
They've all learned that, if they can be trusted to go back home by themselves, they get more time out of their tanks - to such a degree that Tsam, Frank and Jacques are allowed their independence during the day whilst I'm at work (but NOT all at the same time! Only one dragon out at a time!).
With regards to nail trimming, I've got them all used to sitting on my knee, and distracted with a window. They also get irregular sessions being held at awkward angles (vet handling) - I'm careful not to stress them out, and they get rewarded afterwards. My vet has commented on how well behaved they are when we need to make a visit
Oh! I forgot: bathtimes are the only time they're all together - some of the younger ones are still in training, but they're all learning that kicking off and being aggressive in the
bath means they get splashed. Tsam, Jacques and Mocha are very well behaved and calm at bathtimes, and newcomer Frank is learning fast.