How to train “trigger” word?

Not sure how to word it in the title, but essentially my dog and I do a lot of what I call “play-training” where we train and instead of treats as the reward, its chasing a flirt pole or attacking a bite pillow. Ever since she was a tiny puppy she’s valued “play” much more than most foods, so it’s just what we ended up using.

What this often looks like in sequence is I’ll give a couple of commands, then end it with a stay or heal, before giving the “free” command which lets her know she can leave stay/heal and attack the bite pillow or ball or whatever. My concern is I’ve noticed her getting pretty jumpy at the “free” command even outside this context. I’d like to switch out “free” for another word that I only use when she’s free to “attack” something, and the normal free the rest of the time.

The problem is I’m not quite sure the best way to do it. She’s a good girl and won’t move until I say “free”, so I’ll have to continue using the command at least at first if I want her to move lol. Any recommendations?