Something special that should only be had or should only happen infrequently.
You can only have grandma's special home-made cookies a few times a year, and only for a small portion of your life until she passes.

"She only curls her hair a few times a year to keep the grandma's cookies effect."
by Qweenqwillava May 4, 2014
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To paint one's penis green and then put cookies in their grandmas ass, and then put the penis in the ass.
Her: How was the family reunion?
Him: It was a total Green Penis Grandma Cookie!
Her: Holy FUCK!!
by Professional Educator September 22, 2020
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