Originated from anal connoisseur Aaron
, to receive brown balls is to penetrate a female, or males rectum; and during anal intercourse the penetrater will slap his testicles against the person's gouch and lower region on the asshole
Assuming the man or woman hasn't wiped their poopers in some time, the testicles will turn brown from the fecal residue.
Aaron "Brown Balls" is the king of all things fetish. He probably has brown balls right now.