The mouth has many different habitats — the nonshedding hard surface of the teeth, the soft, papillate surface of the tongue, the smooth inside of the cheek — and «what grows on the tongue is very different from what grows on the palate or on the teeth,» says Mager. (discovermagazine.com)
Brush inside of the cheek several times with some vigor (but not enough to cause bleeding). (italiangreyhound.org)
After vigorously swabbing the inside of my cheeks, I seal - locked my specimen in a plastic bag, overnighted the sample to a lab on the East Coast and awaited the results. (entrepreneur.com)