The best thing for you to do fill up a condom with the piss and put it in your cooch. When it is time to piss poke a hole in the condom and let it come out. It will come out as the same rate, stay at body temperature, and not feel uncomfortable. My X gf was on probation for 2 years and did this every time. She wore a ring on her finger that had sharp point on it so all she had to do was slide her underwear to the side and it look like she was adjusting anyway.
Edit: this still works with a tampon in