Ted: Trust me, not only do they tell each other everything. They want to know everything.
[flashback to Lily and Marshall sitting at the table while Ted watches TV in the apartment:]
Marshall: So, after the shower, I was brushing my teeth, and I was like, "Oh man, I wanted to have some orange juice, I should have done that first, but I already had the toothpaste on the toothbrush so I just went ahead and brushed them anyway."
Lily: What happened next?
[Ted rolls his eyes]