To masturbate; the stimulation of a male's penis until orgasm is achieved and ejaculation occurs.

rubbin ur penis wit ur hands or objects
it feels wicked good but its not as good as pussy so guys do it when theyre not gettin any

applying lubricant to the penis, then rubbing it slowly up and down while viewing images of attractive woman naked or engaging in sex acts. In time, the rhythmic movement will lead to a build-up in excitement. At this point, your sister and her best mate will walk in. It'll be too late to stop and a sticky whitish fluid will shoot out onto your computer screen. The girls will close the door and you will be left in a state of profound shame.

To masturbate.
Can also be used to unexpectedly shock people.

What a guy will do as often as possible.

Composed of two words, jack and off. See those for the individual meanings.

The act of consuming apple jacks cereal.