when you jerk off too hard, cutting off the circulation, therefore resulting in no sperm leaking.
lonely guy:"Hey I was on this porn website, but i got the iron palm. So, I had to throw in the towel. Literally. I had a towel for clean up but it served no purpose because of IRON PALM"

super stud:"heh, i actually did leak sperm last night while i was fucking your girl"

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