The invention described herein relates broadly to closure assemblies, and methods of use and manufacture thereof. More particularly, certain embodiments relate to assemblies and methods for closing an opening defined by a spout provided on a flexible container utilising a capping member having a plugging portion and a substantially fracturable retaining skirt. Embodiments provide may an adequate seal for the contents contained within bags against the significant pressure placed upon the closure by the often weighty and voluminous contents of the packaging. Furthermore, the closure may be easily and comfortably removable by a user whilst managing the handling of the bag.