The thing is that according to this page I've found: http://www.progress.demon.co.uk/Adul...asm-trick.html you can have your balls totally squeezed while you are aroused and fully erected, and there's no risk of damage because you are only leading the sperm to a open exit, no matter how strong is the pressure applied.
I don't know if this is true so I'm asking you guys because I like the idea but I don't like serious injuries.
Thanks.