Fluffing your whites

Slang for masturbation, not unlike:

Bopping the baloney, cleaning your rifle, flute solo, jerkin the gherkin, pocket pinball, pocket pool, polishing the banister, polishing the rocket, pounding your flounder, pumping the python, roping the pony, spanking the monkey, tossing the turkey, walking the dog, whipping the willy.

Fluffing your whites:
Person 1: Why were you late for work this morning?
Person 2: Sorry, I was fluffing my whites.

Steve: Aww man, my mom walked in on me while I was fluffing my whites yesterday.