I don't often fly, but back when I went to germany on a school trip, on the return flight I got pulled aside into a small room by whatever the german equivalent of TSA is and they swabbed the skin of my belly, and the inside of my bag. I'm guessing it was a drugs check and I must have just looked shifty because I get nervous in situations like that, but I do find it funny that they pulled me aside instead of the guys with me who almost certainly had something on them.

Also my partner has told me that apparently my armpits sometimes smell of weed or beer, despite me not coming in contact with either of those for a very long time, and now I definitely don't want to get taken into a small room by a TSA person (After some googling, apparently those smells can be associated with high stress)