What is Undie Grundie?
1.
The act of inserting a finger or thumb into an unsuspecting victims anus through their fresh new underwear, thus causing a permanent poo stain. If done in a forceful manner, blood stains may accompany the poo stains.
Paul surprised Steve with an undie grundie...a large fight insued.
See
Random Words:
1.
A phrase to describe you just got it on with a girl, usually more than one.
It can be used in past, present and future tense (see examp..
