Whiskey Throttle Issues for New Rider

Been riding bikes for 20ish years and several months ago my 13 year old daughter expressed interest in learning to ride. She’s been riding bicycles since age 7 and has zero issues when it comes to keeping it upright, braking, etc. She’s ridden with me on my bike so I could familiarize her with what braking, turning and accelerating feel like to the body.

I’ve been trying to teach her on a Honda Trail 125 but it’s been a rocky start due solely to whiskey throttling, which I expected but figured she would have picked it up by now. I’m at a loss on how to proceed from here, anyone have suggestions or helpful links to get her over this hump?