'Saturday Night Live''s Vanessa Bayer has been keeping busy during the show's off-season by interviewing musicians on the web series 'Sound Advice.' It's sort of like Zach Galifianakis' awkward 'Between Two Ferns,' but without the ferns.

In the latest episode, she chats with twin sisters Tegan and Sara, and the results are mighty funny. You can watch it above.

Bayer spends the first part of the clip trying to figure out which one is Tegan and which one is Sara, even making them swap seats at one point so she can keep them straight (it doesn't help).

She also makes fun of their recent projects involving Oreo cookies (they sing in a commercial) and 'The Lego Movie' (they sing the film's awesome theme song with the Lonely Island). Bayer also grills them on their self-esteem issues, which the comic mistakenly gathered from the duo's song titles.

Be sure to look out for Bayer's intern: fun.'s Jack Antonoff, who brings some coffee to the set.

Here's that Oreo commercial featuring Tegan and Sara: