keyzer

So i watch a trailer/promo of HIMYM yesterday on the web, and in it a women say something like "are you ready to find out whats it like to be with a real women" to ted and he replys something like "well there must be a first time for everything".

Not sure what season it is from, i'am having truble to find back to the trailer.
Does anyone know which episode this is from?
it's been bothering me all day..