this is when a man or a woman indulges in masturbation as normal. just before he or she reaches climax, quickly presses Alt + Tab on the keyboard to bring up an internet explorer window that they have previouly set up with the image of someone they have been stalking for most of the afternoon on facebook. This results in a more meaningful wank, and thus more enjoyment for the participant.
for example, one frisky summers afternoon you have been secretly surveying your girlfriends younger sister in her daily activities. knowing there is no feasable way in which to fuck her, to maintain your relationship with her older sister the facebook finisher offers the perfect release.