i think yuumi support is strong if it supports a jungle champion. ofcourse max first E and then maybe go for W to get more power. you will take smite and go for chilling and jungle player will go for Challenging. First leach you will smite the buff and let jungler finish it. late game your jungler will be owerpower with you and early game gangs will be a nightmare to enemies. i tried this in Ranked! smite will give you mana regen boost too so you dont need to worry too much when in jungle. if you both finnish your smites before dragon you can take it out fast. (1800hp on dragon: Yuumi smites and then jungler smites so its solid 1800 Damage) chilling smite is good when ganging as it slows enemies and your jungler wont lose his/her smite.