He made a good video on opening the your tight hip flexors.
Kit, if you read this, please do a 45 min routine video where you talk us through the exercises.
Update: Coincidentally, Justin posted something about Hyperlordosis = excessive curvature of the lumbar (lower) spine and/or cervical spine – which among other things is caused by your short hip flexors.
Check out more drills on Mobility 101.
Update: Justin also has quick hip opener stretch.