99% sure those are fugashi, sweetened but otherwise pure wheat gluten. A form of wagashi that I wish they sold here in America just to have the option of taunting people who avoid gluten but don't have celiac disease.
Yes, the stuff that in South Park they joked made your dick fly off is a fucking (semi)old fashioned snack elsewhere in the world.
PS: Replicating what is done in the picture is ill-advised, as sugar does not tend to treat vaginas well; increasing risk of yeast infection and possibly doing direct damage to the mucus membranes.