Cats can be trained to use the toilet.
Dogs drink out of the toilet.
My childhood cat began using the toilet totally spontaneously. My Mom heard running water in there and figured she'd left the sink on, walked in and there was the cat, crouched on the seat, peeing. He seemed to have noticed he was the only one who didn't relieve himself there, and darned if he was going to be the household oddball. It was *fantastic* ... until he started pooping beside the toilet instead of into it. My theory is that the turds splashed him when they entered the bowl, a
completely unacceptable occurrence, duh. What self-respecting cat would put up with such a thing? So he figured beside the toilet was a reasonable compromise.
He was a heck of a cat.
Now, to address your vile slander: our dogs don't drink from the toilet. You just, like, say
No the first time they show an interest in it, and then they don't. Dogs are cool that way.