dick in a box
The act on putting your penis inside of a box and giving it to someone special.
Based on the song sang by Justin Timberlake and Andy Samberg on Saturday Night Live where they played as two early-1990s R&B ballad singers who believe the best gift to give to their girlfriends is their dicks in gift boxes (hence the title of the song, Dick in a Box.).
See also
This tag implicates box (learn more).