G!P Share definition Flag G!P stands for “Girl Penis” which is a girl with a penis. This word is commonly used in fanfiction. “Damn…I wish there was more G!P fanfiction to read but nobody even thinks of writing any. :(“ G!P by Reeeeeeeeë May 2, 2022 0 0 Get merch Get the G!P mug. Buy Now — $32.95 See more merch