Derived from the word driveby or drive-by, a sniff-by or sniffby is the act of checking the levels of freshness/cleanlyness from someone's smell. Example a parent might pick up their baby and do a sniff-by (especially if wearing a onesie or overalls; no easy view at the diaper's fullness). Parent might do a sniff-by on their teenager's armpit, if a shower was needed or how long of a shower was needed. One might do a sniff-by on someone undies (not for fetishes, but to see if they were having an affair). The smell of latex from a condom, semen drippings, or aftershave from recent grooming.

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