well i know some harness come with a extra something for the wearer but really most dont. the wearer doesn't get must pleasure so with a thigh harness (if you look in the picture its a 2 girls using it) thewearing now can get finger banged it opens a whole lot of ideas up.
Dont be closed minded for others pleasure, not everyone is in a hetero couple.
p.s. im sure hetero couples can find ways for this too. and for solo use im sure its awesome.