hey there GSDgurl!

I've no advice on the gas thing, but I can tell you what I
did with Oz on "stay" that worked. I put a flat collar on him
and attached a 6 ft leash. I stood beside him and had him
"sit", then I told him "stay" and also used my hand in front of
his eyes as a hand signal for "stay". After a couple of seconds
I told him "good boy", gave him a treat, then gave a release
word, "done" and walked around excitedly with him.

When I got the time duration up to about 10 seconds, I then
added stepping in front of him. As he succeeded with that,
I then would step back away from him, slowly increasing the
distance and duration as he succeeded with that. Oh and
very important, I would always step back to him, before giving
him his reward, so he was getting rewarded for staying, not
moving. Also, remembering to give him the release word,
after the treat.

As he succeeds, I keep increasing the distance and duration
and adding distractions. I'll have Murph run around him getting
treats, while he stays. I'll dart to and fro trying to intice him
to move. I'll take him to Petsmart (all kinds of distractions there).
If we start having stay issues, then I regress back to where
we were succeeding and start building back up again.

Par...