• Stand facing table or fence etc… waist high or higher
• Bend, with hands extended straight above head, fingers extended and thumbs facing backwards/upwards, so that upper body extends towards the table.
• As arms touch table and body bends below the table the lats will stretch

The same stretch would work if you stand in a doorway hands extended straight above head, fingers extended and thumbs facing backwards. Step slowly through the doorway with hands on the top door jam.