Future Ted: [v.o.] Kids, you remember Marshall and Barney's slap bet. A few years earlier, Barney lost a bet to Marshall. His penalty was five slaps delivered anyplace, anytime. So far, Marshall had slapped Barney four times. Which meant he only had one slap left.
Barney: What do you say, Marshall? Are you going to seize this slap-ortunity or let it slap through your fingers?
Lily: Don't let him tempt you, Marshall.
Marshall: I don't know, Lily. I mean we have a baby on the way. An extra slap could really come in handy.