Ted: And then Marshall tried to storm out, but Lily went for the Hail Mary Pass. Which would mean... [Ted finds a bra under a pillow on the sofa].
Barney: What do you think, make-up sex?
Ted: No, there'd be a bigger mess. Tempted as he was, Marshall was still too upset. [v.o.] He had to get out of here, any way he could. He choose the door slamming it behind him.
Robin: Which Is why this picture is crooked.
Ted: Nice catch, Robin.
Barney: I'll just, uh, take this down to the lab. [Barney grabs the bra, but Robin snatches it away from him]
Ted: Now all we need is a motive. The million dollar question what were they fighting about?
Robin: I know what they've been fighting...
Ted: Bup, bup, bup, bup... There's only one possible conclusion. Lily and Marshall are fighting about peanut butter.
Barney: Ah!
Ted: Lily left the lid off... [Ted put dark sunglasses] and Marshall blew his.