These SO2 gases can dissolve quickly in the saliva in the mouth and leave an acidic taste. Inhalation of high concentrations can cause inflammation (chemical pneumonitis) and fluid build-up (pulmonary edema) in lungs or spasm of the larynx which can result in death.
This is nasty stuff. I know,as a former high school Chemistry teacher, I've been exposed this and other more hazardous materials. It can be overwhelming as Wade has said.