Try this:
*Holding the pinky finger on the guitar body
*Using rubber band around the fingers
*Practicing slowly before speeding up, making sure the pinky stands still
*Guitar spider fingering. Place all 4 fingers on the same E low string, one finger per fret (1, 2, 3 and 4), then put index on the same fret in a string below without moving the other 3, put the middle in the same fret in the string below without moving the other 3... then the ring finger... then the pinky. When you reach the e string, do the same moving from one string to the string above. It will look like your hand is a spider walking leg by leg in the web of strings