When you're fucking some skank from behind, and right before you blow your load, you pull out and scatter it all over her back.
This is where the name for the x-ray machine at airports comes from being that people photographed with these machines appear to have jumped back first on to a cum grenade.
A term used to define when a man prods someone up the arse hole with his stiff penis violently. Often it can be used to describe a person being buggered without permission.
It can also be used in the sense of ridiculing someone verbally in a way where the person can be said to have been back scuttled.
Example 1:
Brian: " . . . i've seen lots of demons before when I was trying to betray God but all the paths of lucifer were lies and he made me suffer with his tool shed. . . "
Terence: "So, what kind of mental image have you got with this Brian guy and the devil in Lucifer's tool shed?"
Mark: His uncle back scuttling him in the toolshed when no one's around.
Example 2:
" Mark really Back scuttled Brian in that debate on the Illuminaticonspiracy forum, Brian was left with his conspiracy pants down around his kankles for everyone to see."