fivenicate Share definition Flag 5 finger sex. In other words masturbation. A long standing numbers joke, as fornicate sounds like it has the number 4 in it. I don't have any plans, so I think I'm just going to stay at home and fivenicate all night. fivenicate by slackersink February 6, 2017 0 0 Get merch Get the fivenicate mug. Buy Now — $32.95 See more merch