2012-06-11
Explanation
A man is lying in bed, apparently after or during an intimate moment with his partner. He holds up his hand, staring at it in amazement, exclaiming "Whoooaaa..." His partner says "Baby, come back over here," but he insists "No... this is important." A glowing bell curve (normal distribution) is overlaid on his outstretched hand. The caption reads: "The fingers of your hand form a bell curve describing likelihood of use during foreplay."
The joke is an observation that the fingers of a hand, when viewed from the front, naturally form a shape resembling a Gaussian (bell) curve -- shortest on the outside (pinky and thumb), tallest in the middle. The comic then maps this shape onto a statistical distribution of how likely each finger is to be used during foreplay, with the middle fingers being most likely and the outer fingers least. The humor comes from the juxtaposition of a nerdy statistical observation with an intimate bedroom scenario, and from the man's insistence that this mathematical realization is more important than the romantic moment at hand. It is a classic SMBC gag about the type of person who cannot turn off their analytical brain even in the least appropriate moments.