I use deep breathing, slow regular deep breaths, usually in through the nose and out through the mouth.

Or counting backwards from twenty.

Or start at your toes, tighten your muscles then relax, then your calves, work all the way up your body.

That rush is part of what makes the whole thing worthwhile IMO.

On the flip side, that Buck likely smelled you at a few parts per million, if he smells the hormone change it is likely to spook him.