Hi Alexis, very interesting question. It is correct that Corynebacterium spp. are mostly facultative anaerobic / facultative aerobic. They are "fastidious" bacteria, which means they grow relatively slow, as compared to other bacteria. Staphylococcus, the other important underarm genus, is generally an aerobic bacterium. Which means that the genus grows much better in presence of oxygen. It is also a fast-growing bacterium (much faster than Corynebacterium spp.). Those two combined means that adding oxygen to the underarms is actually a good idea: it will support the growth of Staphylococcus, and less Corynebacterium. So in case of sudden underarm smells: one should open the arms to aerate, instead of keeping the arms close to the body. Best, Chris