Hm, on the MW, Make sure the shoulder flap is open and that that edge is the bottom edge all the way across your back (if wearing on the right shoulder). this is a great troubleshooting site for the MW.
On the Hotsling, make sure you put the curved seam at your hip. With either sling, make sure the bottom edge of the fabric is at the back of the baby's knees, with thighs up parallel to the floor at your waist, but sitting down into the sling, slightly lower than the knees. Also, in the Hotsling, flipping the top edge of the fabric out and down over the ball of your shoulder can help tighten the top rail. Make sure that top edge is up to at least the baby's armpits, or over the shoulders on a younger baby. HTH!
On the Hotsling, make sure you put the curved seam at your hip. With either sling, make sure the bottom edge of the fabric is at the back of the baby's knees, with thighs up parallel to the floor at your waist, but sitting down into the sling, slightly lower than the knees. Also, in the Hotsling, flipping the top edge of the fabric out and down over the ball of your shoulder can help tighten the top rail. Make sure that top edge is up to at least the baby's armpits, or over the shoulders on a younger baby. HTH!