During training I used "target", but now I just say "walk it" and expect the end behavior to be part of that. I've also heard feet, toes, touch, get it, hit it, and park it. I've heard "easy" as well, but I think that would be mentally hard for me to personally wrap my head around. I use it when we're out running to mean "slow" or "careful" and that's not really what I want on the 2on/2off - I want my dog to drive to the end of the obstacle and come to a relatively quick stop.
Tara NW1 CGC - GSD 2008
Suli - DSH 2006