D-in-D Share definition Flag Abbreviation of "Dick-in-Dick," the popular sex act wherein one man's penis is inserted into another man's. "I thought you said 'D-and-D,' not 'D-in-D.'""--What did you guys do last night? --D-in-D. --Ouch." D-in-D by Kevin the Impious June 21, 2010 0 0 Get merch Get the D-in-D mug. Buy Now β $32.95 See more merch