Abstract: A bottle adaptor to which one or more bottles of one or more standard threaded-tops may be screwed and sealed to allow sipping of the fluid in the bottles through a flexible drinking tube. The adaptor and bottles may be carried in a backpack. One or two bottle receivers include plural standard threads spaced along an axis and a socket for a straw to project to the bottom of the bottle. A fluid passageway from the drinking tube extends to the straw sockets. Each bottle receiver includes a selectively openable pressure relief from the ambient to the space adjacent the bottle threads. A separate tube coupler having barbs for the drinking tube may be inserted into and locked to the adaptor. For a two-bottle adaptor, a three-way valve adjacent the barb or other tube connection may select either bottle or the shut condition.