Haha! Cotton tied under the lid and then both ends tied together to form a loop over the lid so it then suspends in the water in a set place not moving. It's not a floater but a sinker so the weight of the bottle keeps the cotton taught.
The liquid is a colour matched acrylic paint that's been bonded warehouse the water to make it more liquidy when squirted via a syringe
My outfit: K5 gripped - Sigma 17-70mm - Sigma 105mm - Pentax 18-55mm WR - Tamron 70-300mm - Pentax F 50mm f1.7 - Sigma 10-20mm f3.5 - Metz 48 AF1 - 2 x Cactus V2 triggers - Fully portable mobile studio and some mobile strobist studio stuff !