If you're bound and determined, use something to stabilize it. Push it really hard together and use a few toothpicks or some plastic as "ribs", then tape them down. I'd hot glue the "ribs" on the cartomizer first, let that set up, then push down and tape the ribs to the battery body. The idea being that the tape will stretch as the adhesive settles, but the "ribs" will keep it clamped tight against the battery since they have a much greater contact surface area.