A Cue for the "S" Sound
This is a cue we use with Osiyyah (suggested by his ST) for helping him say the "S" sound.
Take the child's arm, put your finger at the child's elbow and "draw" an "S"/snake shape along the child's arm and "land" in the palm of the child's hand. When you start say "sssss" and say that the whole way until you "land" at the end. Then have the child say the sound while you are "drawing" the "S" or snake on the child's arm.