When the "pretzel"-shot is performed it is a good idea to be warmed up properly. Otherwise a strain is easily obtained.

Instead of taking a direct step forward as in ordinary shots, the foot is placed forward and a little bit to the left (right handed player).
But not so much that the opponent can read this and expect a "pretzel"-shot.
The body is leaned to the left and the throwing arm is lead over the head in such a way that arm and body makes a slightly curved line.
The throwing arm is moved forward and the throw is performed.