Tom is dreaming that Emma is back and begins to kiss her... he wakes up and realizes he is licking Mitch's leg.
"We're partners [...], we share everything. We're like... like the balls!"
Tom tries to explain to Mitch why living with Emma was much pleasant that living with him:
Tom: It was great, in the bed.
Mitch: Yeah, I know that.
Mitch: Just kidding.
The aggressions by Mitch wearing an Einstein's mask
A TV show being watched by Mitch: "We're now back with Jean-Louis, who lost his hair and is still looking for it"
Genius Bonus: There is a scene where Mitch draws a complex pattern explaining who wants to have sex with who ("balls flux") and then writes "Relation of Ball" on top of the chalkboard. It is a reference to the Boole Algebra. Note that "Boole" sounds exactly like the French word "boule", which is an exact translation of "ball" (both meanings).