Like the adductors, the parts stretched by Pigion pose are my worst body parts. I think hip flexors and the gluteal muscles are among them. Here are some of the better instructions I found:

http://www.yogajournal.com/article/beginners/pigeon-pose/

(The lotus is just too advanced even for the average beginner, let alone a tight guy.)

I feel adductor range of motion is more widely needed.