baths.
warm baths stimulate bowel movements.
i have both of my dragons trained to go in the tub. some times they go within 2 minutes.
Tasty Treat was a horror when it came to pooping. she went anywhere and would run through it or sit on it.
after many weeks (months? i can't recall how long it took) she finally stopped pooping in her viv. she gets a
bath every other day and will hold it until she goes in the
bath. if she absolutely has to go she goes off the side of her log and no longer "paints" with it.
once they get the idea that they no longer have to have the smelly poop in their home they will prefer to go outside. hopefully. plus hating the baths helped. if she had poop on her she got an extra long
bath with a scrubbing. she was never happy about that, lol.
not sure if or how people train them to go in a certain area of the viv.