A sexual act that consists of one individual using his/her fingers to stimulate a female's genitalia while they inspect a large number of acorns from an Eastern Hemlock tree. Preferably performed in a semi-public area, such as in a city park, arboretum, or in the back of a biology lab.
Guy 1: Those two kids have been inspecting acorns back there for a while! They must really love the environment.
Guy 2: Nah dude, he's just giving her the ol' Woolly Adelgid. Classic.