The law requires service dogs to be trained to urinate and defecate on command. For this reason, I chose to mark these acts with two very innocuous words -- one and two. Ever since we brought Bo home we have consistently marked urination with the word one and defecation with the word two. These words, coupled with high verbal and non-verbal praise, have helped us train Bo to "go" on command. I've seen him respond to these commands consistently hundreds of times, yet I'm impressed each time I experience it. I use these commands before I enter any public facility with Bo and each time they work like a charm.