Tipping it over isn't the problem, lol. The problem is when the water gets low and cups get stuck on heads! I usually use bigger cups but this one was the one I grabbed for myself and they gave me "we're thirsty too" eyes so I gave it to them instead, lol.
They'll drink out of small plastic bowls too, as long as it's up away from the dog. When there's a bowl, Toby sits in front of it a dips his toes in to make sure there's water in it and then he'll settle for a drink, lol.

I noticed Billy...they do look alot alike! Is he a big love slug too?