A euphamism for having sex.
Person: Want to go build a cardboard fort? (winks)
Other Person: Hell yeah!
Person: What were you up to last night?
Other Person: Oh you know, just building a cardboard fort. (winks)
Other Person: Hell yeah!
Person: What were you up to last night?
Other Person: Oh you know, just building a cardboard fort. (winks)
by Shuggy Doo September 4, 2012
Get the building a cardboard fortmug.