When a man is getting a hard-on for another girl, while his significant other is in the area. Applies for the internet or in real life.
Eric was having trouble and getting a bonerdox. While giving his girlfriend directions to the bar, his friend Chelsea was three drinks in and using him as a human strip pole.
When you get done giving the 'ole bone to the beaver and you forget to wipe off the excess juices so they crusty and next time you get a boner, the crust snaps off and looks like dust
Kid: "Is someone in this room smoking?"
Me: "No, that's just my bonerdust from this morning... sorry bro!"