An ostomy appliance body side member or an ostomy appliance comprising an adhesive wafer having a first adhesive surface for securing the appliance to the user's skin, said wafer having a second surface being covered with a carrier sheet which wafer has a hole for receiving a stoma wherein a part of the adhesive wafer surrounding the stoma shows balanced plastic and elastic properties allowing an adaptation of the size of the hole of the ostomy appliance to a stoma by enlarging the hole for accommodating the stoma by rolling up the inner rim thereof forming a torus and wherein a part of the second surface of the wafer surrounding the hole shows surface properties compatible with the first adhesive surface of the adhesive wafer locking the torus to the second surface in its rolled position by the contact between the second surface and the first adhesive surface enables a simple, safe and reliable customisation of the hole of a body side member without the use of tools and at the same time provides means for reducing the risk of causing injury to or constriction of the stoma.