Last night I attempted to use modeling chocolate for the first time. I was making roses. (white modeling chocolate following Toba Garrett's recipe, aged two days) After kneading it, I attempted to use it and it was quite sticky. I couldn't roll it out on my mat or in my hand without it sticking and tearing when thin. I greased mat/hands with Crisco (didn't know what to use for modeling chocolate).

What makes the chocolate sticky/what do I do to make it not sticky so I can make thin rose petals?

Thanks so much!
Karen