i almost forgot about this-
when i was younger, i got sent to a boarding school w strict rules and had to find a clever way to conceal some L. what my friend ended up doing for me, is getting me a magazine, and dropping a few hits on the corners of one of the subscription cards(you know, the little cards inside the mag that are on thicker paper) and that worked really well.
not sure how discreet youre trying to be or if youre trying to hide it, but fwiw we did that several times and i'd say it was successful bc we tripped everytime. like i said we just put it on the corners and tore those chunks out. worked like a champ, and no one ever knew what was up
as far as paper towels go, ive eaten paper towels w L on them from mop up, and i def tripped balls, but who knows how much was on there. id be wary of using paper towels unless you doubled it up or something bc it may soak right through, and im assuming youre not gonna wrap it up in something bc that would kinda defeat the purpose of being discreet..
you know, you could also drop some on the inside of a sandwhich or some food/snacks..if youre not trying to store it for extended periods, and just wrap that up in some foil or put in a snack bag.. ive done that before too. just dropped it on the corners of the bread..i guess if youre bringing it to someone w restrictions somewhere, food may not work..
one last idea i have personally done before is drop some on the corners of the first or last page in a book- you know how theres always a page or two that are on thicker paper than the rest of the book..that works as well. lol, ive had to do what you are doing several times in my life for several diff reasons, and all of those ideas i mentioned worked.
hope that helps brugh! :D