I trained a large (70LB) dog for a client I was house sitting for. I took their dog out side, and caught some of her pee in a 1 pint tupperware bowl. Then I poured a little of her pee on the grass. When she needed to go I took her over to the 'grass', she sniffed and peed. Then she got a cookie. I will say that the 'grass' I had was not a big enough 'target' and pee ended up on the floor around it.