Y'all so like the yam-based lube that Tachibana used was NOT an aphrodisiac. While domesticated yam isn't that bad, touching yam directly can cause itchiness. (You may have to go to the hospital if you touch wild yam, it's that strong, but domesticated yam is much milder and you can safely eat it). So that lube is using yam extract's itchiness as a stimulant for sexual play.
Y'all so like the yam-based lube that Tachibana used was NOT an aphrodisiac. While domesticated yam isn't that bad, touching yam directly can cause itchiness. (You may have to go to the hospital if you touch wild yam, it's that strong, but domesticated yam is much milder and you can safely eat it). So that lube is using yam extract's itchiness as a stimulant for sexual play.