I've never thought of or tried "tickling" the side of a snake's mouth to effect a release- that's interesting- but the tail tip thing, I've been using that for many years- never thought much about mentioning it, so I'm glad you did- it's very effective & I suppose I just thought everyone knew that. I just touch the tail tip- no "rolling"- & it does make most any snake go forward- I'd assume it triggers their instinct to get away from predators that often try to grab a tail tip.