Simple examples:
* The honey was so viscous it barely dripped off the spoon.
* The lava flowed slowly, like a viscous river of fire.
Examples with specific context:
* The mechanic added a viscous fluid to the engine to improve lubrication.
* The artist used viscous paint to create thick, textured strokes.
* Scientists study the viscosity of blood to diagnose certain diseases.
Figurative example:
* The silence in the room was viscous, thick with unspoken tension.
Remember, "viscous" describes something that is thick and sticky, resisting flow.