ok unlike that other guy i will tell you how to do this easily also it is well know and there is no reason to hide it which was sorta a stupid post by him also he lied it does stack bestial wrath.
Moving on you use bestial wrath then dismiss your pet then 2 minutes later when its colldown is over you call ur pet and do it again bestial wrath/dismiss/call/bestial wrath/dismiss/call/bestial wrath/dismiss/call so on
untill you get it the size you want and its permanent. unless a gm changes it cause it can lag the server also if you get a new pet
p.s only confirmed on private servers not asure oficial
p.p.s also dont use on hswow ull get banned lol