"Heron pose is a great stretch which can follow nicely from a forward fold. Here you are getting deep into your hamstrings with the help of the stability of the other foot. If you’re someone who has tight hamstrings, this might make a difference. However, with any hamstring stretch, caution must be used to warm up correctly and always move into the pose slowly. If there is any pain at the attachments of the hamstring (just below the buttock) or behind the knee, stop right away."

"Bound Boat Pose is actually easier than regular Boat Pose with your legs unsupported. This just adds a nice stretch. The main problem for most of us is just getting to our feet if you have tight hamstrings, so don’t worry about bending your knees. Here the trick is the core strength it requires to hold this pose so you don’t fall backwards. Sit up high on your sitting bones. Make sure you are not slumping. Press your feet out against your hands rather than pulling upwards with your hands."

"Here's a great link with a short video demonstrating down-dog http://www.yogajournal.com/poses/491"