ive seen this technique and used it. what u can do is u can feed him his water a little thru his dropper. then u squirt his water in and out of his water dish. get him accustumed to know that there is water in his water dish. and get him to recognize that when u squirt it in and out of ur dropper that this is where the water is. or what i do is that i just use a hamster water feeding thing and mine knows that when i bring that its for water.

these guys are smart animals.