How to Complete a Large Bean Stitch in the Back Loop Only:
[Yarn over and Insert hook into the back loop of the stitch, yarn over and pull through up to working height] 2-4 times (depending on how puffy you want your bean stitches to be or what is called for in your pattern).
Yarn over and pull through all of the loops on your hook.
Your pattern may require finishing with a chain 1, which may or may not count toward the final stitch count in the round or row. Always refer to your pattern’s specific instructions for clarification.