A sexual act in which a woman (traditionally Japanese) pours sake into the valley that appears in a woman's lap when her legs are closed. Her partner then drinks the sake from there. Also can be used to refer to the sake which is drunk in this act.
Called "wakame sake" because the woman's pubic hair in the sake is supposed to resemble soft seaweed (wakame) floating in the ocean.
"She let me drink her wakame sake last night"