Sometimes, in an effort to enhance beauty, women add oils to their baths, resulting in artificially oily skin. Leaving the top off the can for a short period of time will allow some of the solvent to evaporate, thus, thickening the cement. If the can is not shaken sufficiently to mix up the cement that settles at the bottom, the thin layer will not be strong enough to support proper adherence. Not enough time may be given to allow the cement to dry properly, yielding an unstable base. Finally, changing the brand of cement or using an adhesive disc would be a simple thing to try before more desperate measures are taken.
Creases are a constant source of frustration.
Filling them in with a product like Stomahesive Paste or Hollister Premium Paste might be of benefit. The trick is to make a level surface. Be sure to spread the paste with a wet finger to avoid sticking. If the pouch tends to pull lose at a certain spot, a little skin bond cement or some type of adhesive made for skin can be of benefit. Be sure to protect the skin first with a skin prep, skin gel, skin shield or one of the coatings made for ostomates.