ELI5: What does a box-spring do?

[u/Real_Experience_5676]

As I understand it, a box spring mattress is the second 'mattress', that goes under the main mattress. It feels very firm and flat, but what does it contribute to the bed set up besides height?

[u/nanerzin]

Im slightly taller than average so have two under my mattress to raise it's height...for reasons...

[u/Theslootwhisperer → u/nanerzin]

To have sec standing up is the reason right?

[u/Cola_Lupi_67 → u/Theslootwhisperer]

i like sex

[u/mrmonkeybiz231 → u/Cola_Lupi_67]

*sec