I have a method, which I have used on salad dressing bottles in the past.
Take a bamboo kebab skewer (needs to be wooden, not steel, for the texture).
Put a funnel in the bottle's neck.
Pour in the thick liquid.
Put the skewer through the liquid and funnel hole to the bottom of the bottle, or as close as you can get.
Move the skewer up and down.
The liquid ...