This is a sexual act where someone sucks a nut sack with a mouthful of soy sauce. Scientists have proven that the human testicles have taste buds, and they can taste sweet foods and unami, which is present in soy sauce. By filling the mouth with soy sauce both the person sucking the nut sack and the person getting their nut sack sucked can taste it. The person being sucked tastes the soy sauce and the person sucking tastes the nut sack and the soy sauce. It's a win-win.
by FatFatChubbyCat January 21, 2020