Use a glue gun to make a pattern of raised bumps of glue on the surface of the smaller bottle. You can also achieve a similar effect with normal craft glue, just ensure the it has a fine dispensing tip to give you greater accuracy when applying.

Spray both bottles with Satin Super White spray paint

When the paint is dry, apply a thin coat of glue around the large bottle where you want to wrap the string. Coil the string gently around the bottle in a single layer, being careful that your rows touch but do not overlap.

Tie a collar of string around the neck of each bottle.

Note: Always follow usage instructions on the reverse of Plasti-kote spray paint cans.