Hi N.,
I don't really have any guarenteed solution for this problem, but wanted to let you know that you're not alone. My 16 month old son loves sticking his finger and sometimes whole hand down his throat until he gags. He hasn't actually thrown up yet, but he has done this enough to make his face turn red and his eyes tear up. I try not to overreact when he does this. I usually give him something to play with, or switch his toys. I usually tell him "Look Owen has tears. It doesn't feel good. Let's not do that. Let's play with this toy." I'd keep diverting your daughter's attention whenever she does it. As for playing with the vomit, she probably finds the texture interesting. I'd try to find a substitute. My son has lots of books that have places in the story with different textures to feel. I totally understand your worrisome feeling when your daughter gags herself. Every time my son does it, I pray it will be the last time he finds it interesting. You can't really stop them from doing things, make them do things, or make them not do things any earlier than they are ready. You can stay calm and try to teach them appropriate behavior. This is what I do to handle all the surprises that motherhood has thrown me. Someone gave me some advice when I was pregnant and learning about labor and delivery. The woman told me this about labor and delivery. "It's only one more contraction. You can make it through one more contraction. You can do that. You know that there is an end goal. You can make it through just one more contraction." It got me through 10 hours of labor, 6 hours pushing, with no painkillers, and the only person in the room with me who could speak English was my husband. Since I gave birth, this advice has helped me so much. I just substitute the words "just one more contraction" with "just one more sleepless night," "just one more poop explosion diaper," "just one more time my son gags himself." The list is endless... Just think, one day you will look back on everything and just laugh. It also helps us to live concentrating in the moment. Hope that helps.
D.