Place your hand on the air mattress over the air bubble and apply pressure. Push down on the bubble to try to pop it.
Unscrew the nozzle on the air bed and release some air from the mattress. Keep pressing down on the bubble until it disappears. Have a helper unscrew the nozzle for you if the bubble is not near the nozzle.
Add more air to the mattress using an air pump. Continue filling with air until the mattress is full of air or firm to the touch.
Seal the air bed closed by tightening the nozzle.