T5-T8 NSrRl would be a group curve and the dysfunction is named for the freedom, i.e., the patient's freedoms are side bending right and rotating left, his restrictions are just the opposite: side bending left and rotating right.
To perform the ME technique you would stand on the side of the convexity, for a T5-T8 NSrRl, you would stand on the LEFT side, since side bending is to the right (producing a convex surface projecting to the left).
The whole principle behind ME is that you bring the patient to the "feathers edge" of his side bending and rotational barrier. Once you engage the barrier (ME is a direct - engaging barrier, and active technique - the patient does some work), the patient moves to his freedom of motion against the your counteractive isometrically applied force - the physician resists the patients movement to his or her freedom.
So, if we have a T5-T8 NSrRl, you will stand behind the patient, on the left side with his back facing you, MONITOR at the apex of the convexity with the index finger on right hand (at the posterior transverse process), SIDE-BEND the patient to his LEFT, and ROTATE him to his right (to an approximation of the "feather's edge" barrier). Then ask the patient to lift his left shoulder up to the ceiling (essentially you are asking the patient to move to his freedom - or right side bending). Resist his force for 3 seconds, then ask the patient to relax. Repeat this a total of 3 times with a passive stretch at the end. Reassess.
Some addl. notes: Since this is a group curve it is a neutral dysfunction (Type 1) and there is no flexion or side bending components - so you don't have to worry about flexion or side-bending. Type 1's are notated with the side bending component listed first, followed by the roation component (T6-T8 NSrRl) whereas Type 2 dysfunctions are notated with the ROTATION component written FIRST (T8 FRSl). The subscript for rotation left is omitted - side bending and rotation are coupled for Type 2 dysfunctions so it is understood that rotation is to the left.
Hope that helps. If there are any mistakes someone feel free to correct me. I took all of that off the top of my head and ME is pretty intricate so it's possible I made a mistake or two.