i have done this. the moisture content of the item must be carefully judged. if the pot is bone dry, put a damp cloth NOT A HEAVY WET TOWEL! around the entire thing and leave it inside plastic for a short time. an hour or so could give it enough time to even out some moisture and allow you to add a THIN decoration. why do you plan to do two or three coats? is your slip too thin for what you want to do? what technique are you doing?
do not try to wet the item more than it will take to apply a little slip. if you attempt to dunk the entire thing in a barrel of slip and leave it there for a second or so, the new coating will peel off in large sheets as it dries. now you know why you should plan your decoration and get it done at the right time.
all of this takes some judgement which is developed with experience. spritzing could work if you do it carefully and the clay is at the right stage of drying, the problem with spritzing is that it is so easy to do it unevenly and it can form wet drips that run down to the bottom of the item and soak into the clay there.
it is just possible that the flask will not survive no matter what you do. try if for the experience while knowing the risk, that is the life of a potter.
on another day and with a waster pot, learn how much clay will take before deforming. dunk, not slowly dip or drip, a bone dry pot in a tub of water that will cover the entire thing. immediately pull it out and watch what happens for a minute. cut or break the pot and you will see how very little of the clay was wet by the dunking. just part of learning.