Wow, this reminds me of some other incident. A girl I was having sex with suddenly asked if we could do the stand and carry sex position.
As someone that has been lifting weights for quite some time, I am strong but she was a bit tall and on the busty side, weighing over 60 kgs.
So I casually and lauhingly said, "No way! You'll fracture my dick". And she got super pissed and turned off.
No matter how much I tried to explain, she got off me and we took a long break before she got aroused enough to go at it again.