the extra skin (jowls) that hang off the side of the muzzle, and they kind of, well... fluffle!
drooping or pendulous lips
• (n. pl.) The pendulous or overhanging lateral parts of the upper lip of dogs, especially prominent in hounds; -- called also chaps. See Illust. of Bloodhound.
Upper lip pendulous, particularly at their inner corners.
Flews noun plural The pendulous or overhanging lateral parts of the upper lip of dogs, especially prominent in hounds; -- called also chaps . See Illust. of Bloodhound . 
Upper lip pendulous, particularly at their inner corners.
upper lips.
the large, pendulous sides of the upper lip of certain dogs, as bloodhounds. See diag. under