Improved dispensing devices (100) and methods are provided that include a hollow barrel (102) containing the composition to be dispensed along with a piston (120, 220, 320, 420) received in one end (104) of the barrel (102) for dispensing the composition from the opposite end (106) of the barrel (102). At least one tortuous groove (200, 202, 204, 226, 326, 426, 436) extends across the side of the piston (120, 220, 320, 420) and communicates with the exterior of the barrel (102). The groove (200, 202, 204, 226, 326, 426, 426, 436) allows both air and the composition to travel along the side of the piston (120, 220, 320, 420) as the piston advances into the barrel (102). By permitting passage of both air and the composition, the groove (200, 202, 204, 226, 326, 426, 436) eliminates air pockets in the composition while alleviating pressure in the barrel (102) as the piston (120, 220, 320, 420) advances.
