Corrected entry: In S1E06 Lily dresses like a parrot and Marshal like a pirate. At 5 min 03 sec. Lily says that she needs to pee and Marshal goes with her because she wears an elaborate costume. Later in S1E14 Marshal and Lily are trapped in their bathroom because Ted and Victoria are trying to do it in the living room and they do not know that Lily and Marshal are at home. After a while being trapped Lily says that she wants to do something she's never done before, i.e. she wants to pee while Marshal is also in the bathroom.
Gedas Strazdauskas
25th Jan 2019
Correction: Marshal may well have helped her out of the parrot costume, then left the bathroom while she used the toilet. He could then return to help her back into the costume.