taint massage question?

[Mr. Nice Guyâ„¢]

okay so this question is difficult to ask because i dont know the terms or anything.

My girlfriend wants to try this thing she heard about from her friend and i just want to find out if it's safe.

Here's how she explains it:
While giving a blow job or hand job, you rub the area between the balls and the butt (the "taint" as some people call it)

then when it's time to orgasm, she pushes on it a little, and it does something where the sperm is redirected to the bladder, and you just pee it out later.

I was wondering what thats called or how i could find ou more about it?

 

[Kent]

don't let her do it . stopping the constant flow of sperm will eventually make it nearly impossible to ejaculate. I have heard of this move before and I even know somebody who has used it. it is fine at first but constant use can end with bad results.