I have never felt a "need to pee" feeling before an orgasm, but then i dont do G spot play, which is almost exclusively referred to as the type needed to "squirt" which puts pressure on the bladder. Pressure on the bladder, or bladder muscle spasms, can cause you to urinate involuntarily, or desperately need to urinate, just like with pregnancy or urge incontinence. Me personally, I'm convinced that yes, squirting/gushing is pee. The study i have the most faith in used ultrasound to view the bladders of women who claimed to be squirters before masturbation, at the point just before orgasm, and after orgasm. All the women peed before starting, and showed empty starting bladders. At the just before orgasm scans, even those who had only taken 20 minutes to get to that point, they all showed significantly full bladders, and after orgasm/ "squirting" all had empty bladders. The fluid was tested, and was found to be almost 100% urine, just very dilute, although one or two had a small amount of milky fluid mixed in, true female "ejaculate" similar in volume and appearance to male ejaculate. It would suggest sexual arousal and stimulation puts the kidneys into overdrive, very quickly filling the bladder. (I have noticed i pee 2-3 times sooner after masturbation than days i don't, and i have a pretty strict fluid intake and bathroom schedule due to illness, so it's easy for me to track with accuracy) This would make it much more dilute, and have much lower levels of the chemicals that give urine the typical colour and smell we are used to. As it would be less filtered, it may contain sugars, which would also account for the sweet taste many claim it has, as their arguement that it isn't urine. Most scientific studies that don't outright say it is urine, simply quote the much lower chemical levels of things like urea, but that doesn't mean it isn't urine, especially if it is just very dilute from rapid over production.
I mean, if the testicles can only hold the ammount they hold, where on earth could there possibly be some hidden gland etc that suddenly produces cupfuls of fluid from a female? It would also be counter productive for reproduction to have a flood of fluid, especially as it is debated if it comes from the actual vagina like natural lubrication, or the urethra.
Did you pee? I'm saying yes, but the majority here will disagree with me. If this is a good or bad thing, is up to you. If you find the feeling pleasureable, are ok with cleaning up after, or taking precautions before it happens to contain it, then it doesn't really matter what the fluid is, pee or not.