Most importantly when making this shot is the point of contact of the shuttle. One must control the arm swing. To make a good rear court overhead slice drop shot, salve you must contact the shuttle at the highest point.
After contacting the shuttle, your arm should only move slightly. Do not swing your arm downwards when making this shot. In shot, avoid swinging down your entire arm during the instant point of contact.
If the shuttle reaches the rear court of your backhand, tilt your body sideways with your eyes looking at the shuttle.
Make sure the point of contact is the highest and should be slightly forward of your left shoulder. After that, begin with your forward stroke, pronate as you prepare to hit the shuttle.
The racket head should slice from your right towards the left and contact the left portion of the shuttlecock to avoid the shuttle of going out of play.
Try to refrain from using too much strength to swing froward and downwards. While exerting force forward, use the thumb and the index finger to control the racket head. Slice it and bring it down.