James makes a reference to being a vigilante like 'Clark's friend' to whom Winn makes points at the side of his head like spiky ears. These are indirect references to Batman.
At the DEO, Winn whistles "Super Friend," which Kara and Barry Allen sang in the musical crossover episode titled "Duet" ("The Flash" season three, episode 17.) Jeremy Jordan, who plays Winn on Supergirl, played Grady in the Flash episode "Duet". He played the piano for Kara and Barry while they performed "Super Friend."
When Winn is talking about Markus and his mom going all "Carrie," he's referencing the Stephen King novel turned movie, "Carrie," about a teenage girl with telekinetic powers.