Goes off
From sciforums_encyclopedia
When something Goes off, it is usually a bad thing. This term is typically used when something triggers a malevolent or violent event.
A bomb goes off when it explodes.
Your mother goes off when she catches you doing something wrong.
An alarm goes off when it's triggered by a burglar, or when it's time to wake up and go to work in the morning.
Or your penis goes off just before you enter the snatch or cunt.
