After learning a simple tune on their guitar, each student has to write their own lyrics (or borrow some), film themselves playing (and singing) the song they just created, and send me that video. All of this on day one of a 3-month course. It doesn’t take long, everyone can do it (and has), but it will definitely make you feel uncomfortable.
Ever since I experienced that whistling mishap, when I try something new or scary I start by identifying the worst case scenarios to I see if I can provoke one as soon as possible. I actively look for the feeling of freedom that comes right after. The feeling that creates an environment that allows for huge leaps in the learning process.