What is Manual Rickroll?
1.
In the heat of the moment you forget to line up an actual version of "Never Gonna Give You Up" when rickrolling someone, so you just start singing the song yourself. The overall shoddyness and ill preparation of the manual rickroll prank actually make it much funnier than the automated version.
fred: hello?
ginger: uh, never gonna give you up, never gonna let you down...
fred: ah yes, the manual rickroll.
See