If your partner agreed to occasionally drop a key phrase into the moment, just to really throw you over the edge, what handful of phrases would you request?
For me, the classic "I'm blowing up like a balloon," is impossible to not include, and with my buoyant fantasies, "Hold me down, I'm gonna float away," would also work a treat. As my inflation tastes have expanded, she could also mention that "You're getting too big, I can't hold you down," with significant impact.
My all time favorite during RP is "Oh come on, you can still get bigger" or the variants "You still have some room to grow" or "Lets test how much stretch you have."
Life is always a bit better once you pop a few buttons.