I just have it held bud , not pulling it , not harming the pup in anyway. Back feet pulled back and splayed your finger is white with the pressure ... You may not have intentionally been pulling to hard but you definitely were ... Running dogs need that tail as a rudder ......
The pup was standing that way , as she was watching my other pup a short distance away , I literally held her tail upward, my hands , face , back and arms were fairly badly burnt from the sun so I'm pretty sure the slightest pressure would make them go white.