We used to take those ketchup packets and twist them in the middle a few times, then fold them in half. Next we'd place them under the little legs of public toilet seat lids. When someone sat down, pow, ketchup all over their calves.
I guess we were kind of butts in high school, but it still seems kind of funny to me.
I like the idea, what about using some other, less delicious material as the masking agent though. I think they make some really thick craft paints or rubber cement type of thing like that in a similar applicator. That might be worth a shot.
I don't even really like ketchup.
Madda
Trifles make perfection, but perfection is no trifle. -- Leonardo Da Vinci
Tact is for those who lack the wit for sarcasm.--maddafinga