apparatus and methods are provided including a patch assembly configured to deliver a substance through a subject &# 39 ; s skin . a frame surrounds at least in part an open portion of the patch assembly , such that a region of the skin is exposed through the open portion when the frame is placed on the skin . a substance support area is foldably coupled to the frame at a foldable joint . a substance delivery area is adapted to be placed in contact with at least a portion of the region of skin , by the substance support area being folded with respect to the frame . a stiffener , disposed on the substance support area between the foldable joint and the substance delivery area , is configured to facilitate the placement of the substance delivery area on the portion of the region of skin . other applications are also described .