Correct Tendons is actually two points that are needled together. They are also called Zheng Jin 77.01 and Zheng Zong 77.02
Zheng Jin is located half way between the Bladder and Kidney meridians on the posterior lower leg between Bl 60 and Ki 3.
Use 50mm needles here to get through the Achilles tendon and touch the bone very lightly. Use a light tap to touch the tibia and then back off.
You'd think this might hurt, but it doesn't. The Achilles tendon doesn't have a lot of nerve endings here and it's fairly painless.