Prepare the body first
Looks easy, no big deal... feet together knees out wide and fold. Wait, where the oil can?
This pose of deep external rotation to the thighs, takes open hips and patience. If you have tight hips, back and thighs then start off seated on a block or blanket. This will lift your sitting bones and allow the thighs a depth that seated on the floor wouldn't be possible. Think about the place where your thigh and gluteus meet... try to get more of that to the floor - heavier, rooted. Think about the thigh and not the knee, descending.
Prepare the body first. Sit with feet mats distance and knees bent. let your knees rock side to side aiming for the floor, like windsheild wipers. Eventually bring both feet in together, as close to your groin as is comfortable - really find comfort, we will get deeper in a minute.
Press the sitting bones in to the mat and lift the spine up. Think about your spine lifting up to the sky, as you lengthen up you are taking some of the sinking heaviness out of the hips. Connect in to the lifting, lengthen and elongation of the torso.... belly, ribs, waist, neck. Feel the groin and allow a few moment for it to deepen. Now scoot the hip, one at a time, inch by inch closer tot he feet if you can. This will keep the flesh to the back of the sitz bones and help the pelvis sit upright. Press the soles together, and if you can unroll them like the pages in a book. If the ankles and knees can do this it will help to open the thigh. If not, no bid deal.
Start to fold forward, lifting upward from the bellybutton, and moving forward from the heart. Here is the key... If you are trying to get somewhere (farther down for example) then the thighs fight back and the very muscles you are trying to relax and stretch- well they are the same your body is using to curl in. SO don't curl.