I usually do that at home, but I have tried that a few times, and I must admit that it is an huge turn on - a mix of the thought of being caught, of be alone and free in the Nature, and the total freedom of expelling freely just when you want and where you are - I really liked it.
No problems with the equipment, since I am only in the "Fleet stage", so it is very simple and practical.
I did that in the woods, in a big area not far from my home, despite I live in a well populated area, where some people go to take a walk - a small chance of being caught. My procedure:
Park in the main road, go the woods (not too far, just to not be seen from the road), insert (mmm...) and walk and wait for the effects, and when the urge is too strong, take off my shorts and pants, keep walking with my shoes and a shirt just covering my lower parts, and then freely let out a strong gush (standing is even better) and still walking until the next expulsion... real amazing feelings...
But the second time I had problems, I just let out an huge gush of poo and I heard an old motorcycle coming (it is forbidden there), I had no time to put on my shorts, just to hidden behind a bush... so much space there and the guy almost tread the mess I did a minute before...
To be done just sometimes...