I sit down on the tank itself, wearing only a pair of black panties and a black bra, both made to stretch a considerable amount. Under me is a helium tank.
I push my brown hair out of the way, my green eyes glistening. I take the hose of the tank, and put the nozzle in my mouth. I turn the valve, and a rush of the gas goes into me.
First my stomach expands, filling divinely and quickly. Already I look like I should be carrying twins. Next were my breasts, filling evenly, and quite well. The pressure was building already, thirlling me.