A vehicle side air bag assembly (16) includes a resilient bolster (17) that is located on or adjacent one lateral side of a vehicle seat back. The bolster (17) includes a frame (22) supporting a foam pad (30) within a trim (32) having a release seam (34). Deployment of an air bag module(36) the bolster (17) is controlled by an air bag guide (42) which has a pair of flexible panels (44, 46). One flexible panel (44) has an outer extremity including a first connection (50) to the bolster and the other flexible panel (46) has an outer extremity including a second connection (54) to the trim cover in a spaced relationship from the first connection.