Can someone please explain how exactly cholesterol modulates membrane fluidity? I understand that it reduces fluidity at warm temperatures and maintains fluidity at cool temperatures but why is this the case?

Thanks in advance.

Two important characteristics of cholesterol were determined in 2002. (2002, JACS, 124:4253)
This experiment demonstrated that cholesterol does not randomly integrate into bilayer membranes.
1) Cholesterol favours phospholipids as neighbours over itself or other sterols.
2) Cholesterol favours longer phospholipids over shorter phospholipids as neighbours.
It partitions up the membrane - partly facilitating the existence of lipid rafts.
At high temperatures long chain phospholipid tails rapidly spin underneath the cholesterol, preferring to be beside it, increasing stability, opposed to being beside another phospholipid, which is less stable because it cant move around as much? Something like that I think... And like previously stated prevents packing at cold temperatures.