Pee instead of Ejaculation

Patient: Right, this might take a little while to explain. I’ve come to the point with my girlfriend when she wants to try oral sex with me, and I’m very worried that I will pee in mouth instead of ejaculating. Firstly, I’m asking because she tried and the sensation I felt was similar to what I’ve had when masturbating in the shower, using soap or body wash. Now, when I’ve done this in the shower, I’ve always let out a stream of pee instead of semen. I can ejaculate normally by moving my foreskin back and forth, but direct stimulation of the head by either soap (or even my spit) causes me to pee. I don’t think it would be good for either of us if I were to pee in her mouth, which is my main worry, so please, any help would be appreciated.