Weird question, but completely serious, how are you supposed to check for testicular cancer?

Well there could be sudden onset of symptoms like change in the frequency and amount of urine, or pain during sex or while urinating. Some people may even present with blood-tinged urine. Those are acute and obvious manifestations. But they are not specifically caused by cancer. It could be a result of other benign conditions too like BPH. They only way to screen testicular cancer is through PSA test which is a blood test.