Abstract: A pressure applicator useful in expelling air from a flexible liner enclosed within a thin-walled shell of a nursing bottle comprises a pushrod having a clip at one end for attachment to an edge of the shell. The opposite end of the pushrod includes an orthogonally positioned pad that is insertable into the shell from one open end to compress the liner, thereby expelling air through a nipple positioned at an opposite end in communication with the liner. One embodiment of the applicator is a unitary structure whereas other embodiments disclose separate pads which are attachable to either an end of a pushrod for air expulsion or to a side member of the pushrod for storage. Another embodiment includes a pair of protuberances on the pushrod that frictionally engage corresponding slots in the shell for attachment thereto.