This exploit may work with other forms of "liquid" areas that you can swim in that cause you to take damage, but I have only tested this in the lava in MC and BRD.
The exploit is rather simple. Each second you are in Lava a DoT ticks you for a certain amount of damage. What you do is, while swimming in the lava, keep your camera above the lava at all times, and while swimming, spam your Space (or whatever you Jump with), and as long as you jump the second you hit the lava, you will never take any damage.
This may not be of much use to many but I've used this to farm the last boss in BRD very quickly by avoiding damage that would kill my twink in a few seconds.