When you eat something with too much green pigment in it and your fecal matter comes out green. May or may not also be hairy.
Friend:"Yo you wanna try some of this guacamole?"
You:"Nah man last time I ate that I got da grinch shits"
Child:"What happened to all of the christmas presents?!"
You:"Well I had mad grinch shits last night, so it probably came back and stole christmas."
You:"Nah man last time I ate that I got da grinch shits"
Child:"What happened to all of the christmas presents?!"
You:"Well I had mad grinch shits last night, so it probably came back and stole christmas."
by Turhamkey March 16, 2013
Get the Grinch Shitsmug.