Apparently, it's not where you think it is (and yes, he tested).
http://www.businessinsider.com/the-...-2016-9?utm_source=feedly&utm_medium=webfeeds
After reportedly suffering a bee sting on that most sensitive of male body regions, the testicles, Smith was struck with a curious question that — if this were not for science — would certainly cross the boundary into pure masochism.
Smith wanted to know where it hurt the most to be stung. He devised a plan to sting 25 different body parts, using guard bees from the same hive. He randomized the order of the stings so he'd let a bee sting each body part three times, for 60 seconds each time, enough to inject a full dose of venom. He received three experimental stings each day along with two daily "calibration" stings on the forearm.
He rated stings from one to ten (most painful), with a five being the middle ground. And since each body part was stung three times, he calculated the average.
http://www.businessinsider.com/the-...-2016-9?utm_source=feedly&utm_medium=webfeeds