bull dog Share definition Flag The act of puting ones balls between their legs and preceding to moon sombody. Dude, im totally going to bull dog that car. bull dog by Anonymous May 28, 2003 Words you can keep railfan mug chonk mug chud mug based mug 67 mug slime mug mogging mug chopped mug thot mug glazing mug huzz mug yams mug larp mug unc mug cracked mug simp mug baddie mug bop mug lolcow mug