Before stretching the strap, inspect on the of the strap for a joining line. of the strap for a joining line. Occasionally, a joining line will be present and is indicated by a faint line through the underside of the strap. While the strap is very strong, if you stretch the strap directly on a joining line, it can break, so never stretch the strap directly on a joining line! See the below photo of a joining line:
To stretch the strap, simply hold the strap between your fingers and in small little increments stretch each section of the strap where it feels too tight. You can do the same for the toe pole if this feels too tight. Continue to do this, trying the thong on and off, stretching the strap and toe pole until it has reached your desired level of tightness.