I have a problem with getting bj’s

First off, I go crazy for em. But I have an issue when it comes to finishing. I don’t know what it is but every time I get to that edge a part of me holds it back because it feels like I’m gonna pee instead of bust, and I’m not sure if it’s because of something I did when I would jerk off and it trained my body that certain pleasures activate something idk. I’m at a loss at this point when it comes to this because I don’t know how to change my mentality and with normal sex it’s like a regular finish but when it comes to bj’s it’s a different story. 20m if someone has advice or something it would be nice to hear some tips or something