I use "Splat" with newer students as a way to open the chest and under the arms in preparation for Wall Dog or Down Dog. Also, it is a nice way to start to arch the back without too much effort.
Step 1: Stand about a foot away from the wall and extend hands up the wall.
Step 2: Tip pelvis forward, lifting the tailbone.
Step 3: Allow heart to start to move towards wall as hands continue to stretch up so there is a sense of traction.
To release: Allow tailbone to descend and slide hands down wall and transition to Half Wall Dog.