I don't know why you're talking about cupping and the prime minister.  I've had cupping, as part of a treatment for a back spasm along with a massage.  I don't know/think that it helped, but it didn't hurt.  It's not like he's going around telling people not to vaccinate their kids, or that a spoonful of cider vinegar a day will cure cancer.  Better we have a PM who cups than a President who drunk-tweets.