An expert in the area betwixt the anus and genitals that also is particularly outspoken in their art, so much so that they claim a self-declared royal authority of all things grundle-related.
The grundlefinger can be any meta carpal used to massage or tenderly probe the grundle area. Also any person who resembles a small monkey. In portugal it is a common insulting hand gesture
Hey. Get that there grundlefinger out of my gazpacho! After that d bag cut me offin traffic I gave him the old grundlefinger.
The act of fellatio performed on a man who is having a bowl movement on the toilet. iow, giving head to a guy while he's taking a huge dump.
Referenced briefly in the american pie: beta house movie, wherein a test to join a fraternity includes the requirement of receiving said carnal pleasure.
could possibly refer to the act performed on a woman, but the logistics are much more complicated
"Yo, your mom gave me some grundleingus last night."