Jefferson Curl - breathing

Hi guys,

Specifically how do breathe as you do a Jefferson curl? _{..Just curious...}

in - out ... repeat!
Just kidding   I don't know about any do's and don'ts but I treat it like most stretching and mobility routines: In on spinal extension, out on flexion = I  breathe out when I fold forward, usually do another in-out while at the bottom of the movement to get a deeper stretch and relax into it, breathe in on the way up. I also focus more on breathing into the belly than the chest.