and blocking members in an engaged and locked position is shown in fig2 b as the ramped surfaces 204 and 206 slide over each reaching a locking and blocking position described above a positive audible feedback such as a clicking noise may be created which indicates that the unreleasable one way coupling between the reservoir 30 and the feeding tube assembly 40 is completed the blocking member 203 and the ramped surface 204 of the neck 200 as well as the blocking member 205 and the ramped surface 206 of the feeding tube assembly 40 are preferably positioned such that a positive blocking and locking affect is accomplished immediately when the feeding tube assembly 40 is screwed onto the neck 200 the above described unreleasably one way coupling is possible with the selection of the material constituting the neck 200 and feeding tube assembly 40 such that some deformation of one or both parts takes place during the engagement of the ramped surfaces it is noted that proper tolerance as well as proper material selection between the coupling parts is essential to ensure that the ramped surfaces are able to slide over one another into place the locking and blocking members in a.