They are made of cool wax, but when placed in hot hands, they melt.

This poignant couplet uses the metaphor of wax to describe the delicate nature of the beloved's heart or affections. Mir Taqi Mir suggests that while the heart might seem solid, it is inherently fragile. It can melt away, just like wax, when exposed to the slightest 'heat'—be it intense passion, memory, or emotional turmoil. It speaks to the extreme vulnerability of love.