How do I do Reverse Kegel without peeing?

Male 18. I've been starting to do Kegels and with them also the reverse Kegels. My problem comes when every single description of the exercise says "The Reverse Kegel is like pushing out pee, but without peeing". Now I've been doing it for a few days but it seems like I can't fathom how to pee without peeing.. Please help.