The practice of a girl furiously masturbating while she and others have gone for a wondle

A brummie word for pleasuring oneself.

to try and molest one at the movies

To pleasure oneself

to creep up in the background of pictures on multiple different occasions. This is usually done on purpose to "ruin" pictures. I can be perfected easily with good timing and unique facial expressions.

The act of screwing someone over badly - having concealed your true motives by lying and keeping secrets, then suddenly dropping the bomb out of the blue. Joshing is a specific kind of deceit where you try to blame other people by using their outrage as incriminating evidence while getting rid of any evidence pointing to you.
Honorary mention just popped up in xkcd comics.

Famous people who claim to have been "Joshed" include O.J. Simpson and Robert Blake.

To "fall" or leap from a company ladder in order to get a workman's comp funded Vicodin prescription.