Don’t “stroke” it. Hit a “chip-putt.” From longer range a chipping-type motion gives the shot enough gas. It’s easy: Let your arms swing down from your taller stance. (Save your “stroke” for shorter putts.)
If after a few swipes you feel substantial resistance and can’t get the club through the grass with good speed then this isn’t the lie from which to flop. Abort! Hit a safer pitch. (For all of Phil’s thrills he only flops it when he’s comfortable doing so.)
At address hood the clubface by turning in the toe and position your hands even with the left side of your chest creating some shaft lean. This encourages you to swing down sharply into the bunker one inch behind the ball.