Hello fellow guitarists

Lately I've been on a large Tommy Emmanuel binge. I've been watching tons of videos of him playing and so far I've been able to complete two of his songs. The next song of his that I'm trying to learn is called Lewis and Clark, and this one in particular is giving me alot of trouble.

In the chorus of the song, Tommy plays what appears to be an open emin9 chord while fingering a D note on the 2nd string with his ring finger. On top of this he is playing a melody on the 1st string. The melody starts with an open E on the 1st string (note that all of his fingers are stationary at this point). The 2nd note of the melody is an f# on the first string. To play this note Tommy rolls his middle finger downward in order to bar the note while still fretting the 2nd string with the same finger.

This is hard to explain so I'll leave a link: https://www.youtube.com/watch?v=Y1pS_6hErDA

skip to 1:50

Bending the 2nd knuckle of my finger is something that I'm finding incredibly hard to do. It's somewhat painful to pull off. Painful in a way that's hard to describe. My mind screams at me to stop bending my finger even though it actually isn't all that painful. The best comparison I can think of is that it's annoying almost in the same way that scratching a fork and knife over a plate is if that makes any sense.

Is this something that is achieved with practice? Perhaps the 2nd knuckle is flexible and will bend back further over time, but I'm not sure, and I don't want to hurt myself finding out.

Any advice is appreciated. Thanks