What is Premature Send-jaculation?
1.
When you send an email before you're ready to send.
You might hit send accidentally or your cat walks on the keyboard and sends it for you or the next thing you know, the email has been sent even though you haven't even touched the keyboard.
The prematurely send-jaculated mail definitely isn't ready to be sent as it might be halfway written, have a lot of typos, or be too rant-y or stupid to be sent, hence causing embarrassment when the email reaches the recipient.
Co-worker to another: I just hit the wrong key and sent half an email to the boss that I shouldn't have!
Another: Premature send-jaculation is dangerous, hope you don't lose your job dude
See
