End of a thumb era?

Since she was small enough to find her thumb, it has been a near permanent fixture in Sof's mouth. It has been enough of a constant, that it's now just part of her persona.

I had sort of hoped the habit would diminish on it's own (wishful thinking, I know), but now that she's getting older it is time to take action! Enter :

We started this morning, so she has the weekend to get used to it, and so far she's trying to tell me it tastes good (hah!!), but the gagging that ensues after she tries to suck her thumb tells me otherwise.