An oral sex position, in which the thrusting of the penis, is rapid, and quick in succession.
Both partners are facing the same way.
The Receiver (the one being sucked) is in a standing position, with their legs spread slightly apart.
This is to allow the Giver (the one doing the sucking) to sit beneath the Receiver.
The penis is placed within the mouth, and the Receiver then does some basic downward thrusts, in a repetitive motion, simulating the action of a jack hammer.
The Giver usually is able to position themselves, to also fondle the scrotum.
They can also better use their hand, to help stroke the penis, as it is shoved in and out of their mouth, controlling its penetration.
Usually their body is forward of the Receiver's body, while their head is underneath.
Usually denotes a more aggressive form of thrusting, whether during oral sex, or penetrative anal sex.
The motion is far more rapid, creating hard short thrusts.
Can also be referred to as Pistoning. (in reference to the thrust motion)