Depends. Cubicles in public toilets can be tricky.. So I imagine!!! Having sex in toilets is one of those things though, sounds kind of kinkier and cooler than it actually is. I like to keep my love making and my pooping separate thanks.
This can be a little risky as their are pathogens and bacteria present in a toilet environment. Why not save the love making for somewhere more romantic?
Anyway, if you are determined to have sex in confined spaces like a public bathroom, then the standing up position may work best as it requires little space.
Having toilet sex is easy as long as you can get the right angle. Face to face is best only used in really narrow toilet cubicles for example, where you would insert the penis by sliding up from underneath.
Otherwise, if you have the room, get her to lean forward and come in from behind. If it's two guys, then the same applies.
Toilets are also pretty good for oral sex because you don't need as much space.
Some people use the toilet furniture for leverage too. Like the Yankee fans who were caught on camera ...While in really small spaces like airplane toilets you might need to even sit on the toilet to make it possible