Hi Everyone! I'm new and I cant seem to get these roses right! I used the basic wilton buttercream with shortening and all but the roses seem to break on the petals near the top. They are ruffled almost as if tearing. I've tried piping gel, really still icing, semi stiff, light corn syrup, and trying to open the thin end of the tip but it doesnt seem to work. Any ideas? Thanks!