Testicles are the sperm producing sacks of a tubing, that is unrolled, would be extremely long. Like more than .2 miles. thats a lot. usually, when a male is struck in his sperm producing sack, containing 2, or more smaller sacks, that directly produce the sperm, he cripples in agony. many women find this hilarious, while other males grab their own sacks, and try not to feel in too much pain.(yes we all got your back, Mr. I-just-got-kicked-in-the-balls)