Well i am so sad that Leavanny just isnt that good. I used it to advance through the main storyline but when teams a well rounded and multityped its really is useless. So i have decided to go with an idea on swadloon cause he was annoying to level up but a good tank if used right:

Camouflage (get rid of horrible defensive typing)
Payback (so your not tauntable)
Toxic (just to be annoying)
Rest (used with leaf guard to really have fun in the sun)
IV's just make sure it has horrible speed so payback gets its double power
Ev's 252 to each defense and four to HP
use this set with leaf guard and a sun team for a different and slightly unexpected Toxic stall
Will Reiterate that leaf guard and sun is real important because it allows you to heal, couple that with camouflage and youll be in for a while.
one counter i can think of is Coballion cause it resists toxic and gets a boost off of payback so just watch out for that if you use it