For more localized pain more precise acupressure/puncture is used.
The point is on the line which goes down from the middle of the axilla
and is located halfway between the 11th rib and the axilla[the 12 the rib is the last rib]
To get an idea look at the video: start looking at 12.22 of the video to find Sp 21
Let me know if it was of use to you.