Green’s Dictionary of Slang

rays n.

In phrases

catch (some) rays (v.) (also bag some rays, cop..., get..., grab..., lap..., soak..., take..., catch sun, catch sunrays)

1. [1960s+] to sunbathe; thus backform. rays n.

2. [2000s] (US teen) goodbye, a feasible alternative farewell in sun-drenched California.