No ideas just my grossed out condolences,lol. If it is any consolation I have heard of children that do this. More so when it is meal time and also in older children who have some control over what they are doing. This one is a bit young to be gagging herself on purpose so it might just be happenning since she eats just before nap and then lays down so it is easier to do. When she wakes can you just get her up and put her in a highchair. At least you will still get a bit of a break. The idea being not letting her make a mess you have to clean up but not letting her get up to play or eat either.