I use this simplified version of the B-skip drill to effectively relieve soreness in the ischial tuberosity (the area where the hamstrings attach to the pelvis) and stretch and strengthen the hamstrings and adductor.

Many runners get pain there, particularly if you're sitting at a desk all day. The key to doing this exercise right, is to keep the foot in the dorsiflexed position (toe pointing to the shin), straightening the leg once the knee is horizontal and then pulling down in a "pawing" motion with the leg, instead of kicking out. It takes some practice getting it right and feeling it in the attachment.