First of all you need 3+ high lvl TH's. PW & AW could be too but TH's would be better. This trick consist on spamming by them skills Trick/Switch on RB. While they will be using it, RB will stand in one place and wont do anything. So others can hit him without any fear :D
You can use it on any kind of RBs ;)
It was tested on IL Dexternet Community but it should work on others servers too.