[flashback to Ted and Robin kissing in her apartment:]
Robin: Wait, wait, wait. We don't want to start having babies right this second. Do you have a...?
Ted. No, I don't.
Robin: Well, we probably shouldn't.
Ted: Yeah.
Robin: Risk it?
Ted: Risk it.
[back at the wedding, Barney notices as Ted is served a bottle of beer while Robin opts for a bottle of water]
Barney: No!