Green’s Dictionary of Slang

cool-off n.

[cool off v.2 (1)]

calmness, relaxation; an escape from controversy.

[Aus]R. Park Poor Man’s Orange 246: All he wanted was to take off his shirt and undo his shoelaces and have a cool-off somewhere.
[WI]S. Selvon Lonely Londoners 71: He thought she gone by tanty house for the usual cool-off.