Crew can't poke, prod, thump or otherwise "touch" customers for whatever reason - tempting though it may be! Sadly, that's really the end of the matter.
One of the joys of being Cabin Crew is that if you get stuck or lost in some way, while at work there are so many experts readily to hand. It turns out that all of our managers, most of our customers and many of our pilots are able to dispense useful advice as a minimum, and frequently to demonstrate how our jobs could have been done even better, especially some time after the event has concluded. I find this hugely reassuring.