Ah. Perhaps it was a
bona fide story. The prof was pipetting glacial acetic acid by mouth, and inadvertently exceeded the maximum recommended volume of the pipette in a single transfer. Later, the entire interior lining of his mouth and tongue peeled off (with no further ill effects). After that, he used rubber suction bulbs to pipette. And aren't you undergrads lucky we have the fancy thumbwheel/plunger pipette controllers in your labs now?
Since I couldn't do it the easy way in an acetylsalicylic acid lab, I had to peel my mouth with the lactic acid from a big bag of Herr's salt and vinegar chips.