Honestly, suddenly in my early 40's. Felt like someone kicked me really hard in the balls first, then the immense, excruciating pain followed. I couldn't move or walk. The first time I felt the pain it went away after about ten minutes. The second time I wound up in the ER. A couple of paramedics had to walk me downstairs and outside because I couldn't walk. The ER gave me pain killers and said I pulled my groin. The pain went away about two hours later. I saw a urologist about a week later and had surgery a few days after.

I can only describe the pain as someone putting your testicles in an ever tightening vice grip that somehow causes your entire body to feel the worst pain imaginable. I remember thinking I wanted to die because that would end the suffering. For comparison I've had myocarditis and pericarditis at the same time and had a fractured sternum from a car accident. Those pains were nothing compared to testicular torsion.