When the slime from a vagina coats one's face after a cunnilingus session and the pubic hairs of the vaginal region become glued in a matted layer via the adhesive action of said slime.

When one raises one face, it appears as if one is sporting a mask made of beaver fur.
"Walter ate me out last night but he was so enthusiastic about it I didn't have the heart to tell him I hadn't had a chance to wash up after shaving. When he came up afterwards to give me a kiss I asked him if it was Halloween because he was wearing a beaver mask."
by Showdown Sean October 29, 2011
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