Empathetic Prostate
One's prostate gland reacting to someone's descriptions of painful experiences, or a reaction to the sight of someone elses painful experience. This is a dull, almost tingly sensation that lasts a few seconds and then disappears into the ether. Depending on the duration and magnitude of the sensation, this could be the equivalent of your prostate crying uncontrollably, or just emitting a concerned sigh.
My wife told me about her mom's varicose vein surgury, and I almost doubled-over from prostate empathy.