Generally you can duck, then jump and stop ducking, repeatedly. Rather like in Mario 1. It's unusual to get stuck, unless you have something on that gives you the powerslide ability (which is very possible). In those cases, you have to be careful not to slide into small holes. Usually if you do, the best option is just to abandon character and keep going -- you don't lose your equipment or anything like that, and character death is a normal and natural part of Environ, heh.
Glad you're enjoying it besides this!