Don't force your hand if it couldn't draw for too long. I've practicing for years so you can slowly practice and gradually last longer when drawing. Good luck though~~
I really love these poses of your characters did you use reference or just draw it by yourself? If so, you should make a tutorial to give some tips for some helpless drawing pose people like me T_T ur just so genius T_T
I really love these poses of your characters
p.s: sorry for my poor English