Nancy doesn’t believe that Robin and Steve’s relationship is actually platonic and assumes they’re fucking on the regular in secret. Nancy gets in a mood and tells Robin that she and her strap-on could make Robin come so much harder than Steve ever could. Robin doesn’t fess up to not sleeping with Steve or being a lesbian because she wants Nancy to actually follow through with fucking her brains out and feels that playing along like “no way, his dick feels soooo good,I can’t believe you left him, I cum multiple times every time, just looking at it makes me drool” and pretending to be a straight girl is the best way to egg Nancy on.