A boundary acoustic waves device includes a piezoelectric substrate having piezoelectricity, interdigitated electrodes formed on the piezoelectric substrate, a first medium formed on the piezoelectric substrate so as to cover the interdigitated electrode, and a second medium formed on the first medium. The generating includes moving a head in proximity to the surface, applying a fluid from the head to the surface while the head is in proximity to the surface of the substrate to define the fluid layer, and removing the fluid from the surface through the proximity head by a vacuum. Feedback may be provided and records kept regarding the virtual world activities and transactions. The plunger is engaged with the inner surface of the dispensing chamber, is capable of sliding in the cavity of the dispensing chamber, and is fluidly sealed to the inner surface of the dispensing chamber.