After a request I decided to explain one of the the methods I use for "WHOA" Here goes: Drive/concrete a post in the ground leaving about 2' or so sticking up, it must be firm, you can use a 1" round steel rod or piece of rebar etc. Drill hole in top or weld a link for a checkcord snap to connect to. Attach one end of a 20' to 30' checkcord to your dogs collar and the other end to the post, attach a second cord/leash about 4' long to your dogs collar, this 2nd cord you will have in your hand, starting close to the post with short cord in hand walk your dog swiftly away from the post until the long checkcord slams him to a stop, WHEN that happens you say "WHOA" holding your empty hand up with palm out! Hold for 10 seconds or so and quickly walk him back past the post and continue until it slams him to another stop and "WHOA" with hand out again! Alternate different directions around and past the post each time, do this about 10-15 times a day for 2 weeks, later you want to transition to a bench and then the ground and then on planted pigeons or quail. I used the word "slam" as an emphasis, it really is not as rough as it sounds, just firm enough to enforce WHOA! I will add more later!