I've always done keep DOTs on the frog, everyone stand in AOE range. I have been having timeout issues recently on the 5f frog because of how often it spams charmga. Last run I went with a new LS, and the wleg RDM was standing outside charm range and Sleepga us > kite, supposedly to ensure DOTs on but also to showoff a little I think.

Anyways, it worked ok on the lower frogs but he ended up getting owned on 5f. So moral of the story: simpler to stand in AOE range, frequently apply / reapply DOT, and preferrably get a stunner of some sort.