When a woman forces a males beard inside of her hoohaa to stimulate her squirter to poroxide the man hair to claim him as her "billy goat " hence being billygoated
When a super hot chick bites the longest part of your beard/goatee and gives it a little tug and shake.
Roy: "She billy-goated me"
Brian: "She just clapped on and shocked you like a rag-doll?"
Roy: "Yeah dude, weirdest and sexiest thing ever. You need to grow yours out."