After listening to a very misinformed explanation about what female ejaculation was by another female, I feel somewhat obligated to cancel out the misinformation and offer a better and more educated answer on what happens when a woman "squirts".
Squirting or female ejaculation happens during an intense orgasm and releases clear fluid from the vagina by stimulating the "G-spot". (I won't go into HOW to make a woman squirt, maybe another time, but for now this is simply what it is). When rubbing the G-Spot either by fingers, toys, or even rubbing it with the penis, a build up of fluid consisting of plasma and mucus releases itself NOT from inside the vagina but rather from a gland...the Skene's gland.
Squirting is not releasing "pussy juice". When a woman squirts it is due to this gland being stimulated and forcibly shooting out a clear, odorless fluid that is not urine but as mentioned, a combination of mucus and plasma. The vaginal wall does seem to tighten upon release of ejaculation but it is not pushing out and substance from inside the actual vaginal canal.
The Skene's gland has an opening next to the urethra that is a bit smaller in size. It has been speculated that not all women have this gland which explains the ability for some women to squirt and others to not have the ability to.
Hopefully people will enlighten themselves by reading this because I was shocked at how many people had no clue how this worked. I will be doing a video about methods of inducing a vaginal orgasm and/or squirting techniques from a female perspective. :-)