I thought he said it about Maya, too, though not sure about that.
Much more likely with Stewie, but ... I would still bet it doesn't happen. Just my guess.
I don't recall Geno saying that about Maya, but he may have.
I think she tried one on a breakaway early on, maybe her first year, and lost the handle on it. I'm not sure if she made the hoop, but I think she did. Geno told her he didn't care whether she dunked or not, as long as she made the basket. That became her attitude.
One factor was that Maya's legs get tired and her lift diminishes over the course of the game. So trying to dunk with 8 minutes left in the game is much harder than early on.
I may prefer Maya's signature finger roll to a dunk. Someday, there will be a statue of that shot.