Donating_英语成人笑话

a man and a woman were waiting in line at the hospital donation center.
man: "what are you doing here today?"
woman: "oh, i'm here to donate some blood. they're going to give me $5 for it."
man: "hmm, that's interesting. i'm here to donate sperm, myself. but they pay me $25."
the woman looked thoughtful for a moment and they chatted some more before going their separate ways. several months later, the same man and woman meet again in the same line.
man: "hi there! here to donate blood again?"
woman: (nodding her head with mouth closed) "unh unh."