The phrase "sticky mess" refers to a situation or problem that is difficult to handle or resolve. It implies that the situation is messy or complicated and could cause trouble or difficulties. Full definition
The dates are also all mashed together in the 2 lb package so I have to deal with a big sticky mess when trying to separate one or two dates to eat every morning. (amazon.com)
This is absolutely necessary, otherwise if you mix in the marshmallows while the peanut butter is still hot you'll melt the marshmallows and end up with a big sticky mess. (justsotasty.com)
I feared the dough would be gooey and messy to work with, but it was quite firm and rolled into balls by hand without a huge sticky mess. (alidaskitchen.com)