Throw In Rule Question

[Amesman]

Originally Posted by BillyMac

During a designated spot throwin, the player inbounding the ball must keep one foot on or over the three-foot wide designated spot. An inbounding player is allowed to jump or move one or both feet.

So the OP got me thinking: If that scenario takes place (running forward, toward the endline), the inbounder can jump but better not break the plane -- with both feet, as it were -- before releasing the ball, correct? Because the inbounder can reach the ball through the plane to inbound BUT also must keep one foot on or over the 3-foot-wide spot. Right? (Never seen it happen but ...)